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PDW Paging Decoder Software


Since 2003, Peter Hunt has developed PDW to the most important (free!) application to monitor POCSAG and FLEX. PDW has many users worldwide, from radio enthusiasts to professionals. After 10 years, Peter considers PDW as finished and he has stopped development. Peter, thank you for all your efforts! Meanwhile, PDW is Open Source. You can read more about that below.

As of March 2013, this site is the official host for PDW.


The latest PDW version can be found here:
PDW Paging Decoder

Open Source

Since April 2013, PDW is available as open source software. This enables others e.g. to enhance the functionality, or to develop a Linux version.

You can find the Github project repository here.


I lack the time to give individual support with PDW. Please refer to the Forum on this site.


Since Peter Hunt took over PDW in 2003, it has been freeware. Although Peter never wanted to earn money with PDW, some people kept on pushing him to offer a donation option.

If you feel like donating, you can use  or consult the manual for other options.

History [click to expand]

Version 3.12 (28 July 2013)


  • Fixed some deprecated coding techniques so PDW can be compiled with Microsoft Visual Studio 2012
  • Fix to prevent filter array overrun when moving items in window
  • Fix in POCSAG parsing prevent buffer overrun
  • Fixed truncated messages in Mobitex


  • Link to PDW-website points to this page
  • Copyright reflects Open Source license

Version 3.1 (26 September 2010)


  • Due to a small mistake, Mobitex could not be decoded via the soundcard.

Block Duplicate Messages

This existing option has been extended and can now be configured in three ways:

  • Previous address+message is the same (no timer)
  • Previous message is the same (no timer)
  • Previous address(+function)+message is the same

The first option compares the current capcode and message with the previous. The second only checks the message text. The last option compares the address (and when monitoring pocsag, also the function number) as well as the message text. This last option also enables a timer (1-9 minutes). If a message is repeated within this period, it will be blocked.

Also, you can now enable or disable the blocked.txt file to which blocked messages are logged.

Version 3.0 (10 August 2010)


  • In ERMES, sometimes the message text was copied after the previous message


As some of you probably already know, RS232 is a standard for serial data communication. The well-known 2 and 4 level slicers which can be used with PDW don't observe the RS232 standard. This is the main reason why additional drivers are needed (comprt.vxd or slicer.sys) and why Serial-to-USB converters are useless. These converters don't only convert the hardware, they also convert the RS232 data to USB-level.

An RS232 interface has been developed especially for PDW, which does observe the RS232 standard. No more drivers are needed, which can solve problems with serial PCMCIA cards, and the interface also allows conversion to USB.

Below are the modes/bitrates which are currently being supported:

  • Pocsag (512/1200/2400bps)
  • Flex (1600bps)
  • Mobitex (8000bps)

Using two DIP switches on the interface, 4 data speeds can be selected:

  • 512bps (Pocsag)
  • 1200/2400bps (Pocsag)
  • 1600bps (Flex)
  • 8000bps (Mobitex)

This means that ERMES and ACARS are not supported and when Flex and Pocsag are combined on one network, only one mode can be decoded at once. Only a combined Pocsag 1200/2400 network can be decoded without having to change settings.

Invert Data

In the Interface Setup window the data's polarity could be inverted, or set to Auto. This automatic detection will now allways be used, you can't select a manual setting anymore.


One of the things which could be found in the Debug window (F12) was the RX-Quality (decoding quality). This value is now being shown below the signal indicator and is an indicator for decoding errors. These errors can be either visible (garbled messages or coloured characters), or invisible (corrected by the error correction). If the signal is strong enough (without noise), an RX-Quality of 100% should be possible.

Version 2.60 (24 March 2010)


  • When using the command file, memory would slowly run short.


The filters.ini layout has been changed. The numbering has been removed and the FilterCount is not more than an indication.

Loading of the filters should be a bit faster, maybe only noticable on slower systems.

7-digit capcodes can now also be saved without two preceding zeros.

When searching for "duplicate filters", PDW will keep on running on the background.

After searching a filter, F3 could be used to find the next filter. SHIFT-F3 can now be used to search backwards.

SMTP port number

The default SMTP port number is 25. You can no also define a custom port number.


The word wrap option has been removed. Internally it is now always enabled, except when monitoring Mobitex.


The two icons to open/close the logfile are merged into one icon. This will open the Logfile Dialog in which the logfile can be enabled or disabled. ALT-L can be use as shortcut to this dialog.

Version 2.53 (11 January 2009)


  • When monitoring ERMES, it didn't seem to be possible to change the color for time/date. By mistake, PDW seemed to use the color of the Paging time/date (Pocsag/Flex).
  • The daily statistics (ALT-S) were logged to the wrong file (the next day in stead of the previous).

Double click / text selection

Before, at the second click the text below the mouse cursor would be selected, regardless of the position of the first click. Both clicks should be at the exact same position, otherwise you can rapidly click on two different words, causing the second to be selected. Should be fixed now.

The double click speed in PDW was fixed, although you can set the double click speed in Windows' Control Panel. This timer is a bit different than the timers in PDW, but I've tried to use about the same time for double clicks in PDW.

Find Filter window

I've made several changes in the Find Filter window. When this window will be closed after searching, you can use F3 to search again, using the same search string.

Because of above change, but also on request, PDW will remember the the 'Case Sensitive' selection for as long as it runs. Before, the selection would disappear when the Find Filter window was closed.

The option 'Search while Typing' has been removed. PDW will now always search while typing. Also, the number of hits will appear, the number of times the search string appears in the filters. This number will be updated after each key stroke.

Filter window

Some extra keys can be used in the Filter window. As in other software, the space bar will scroll down, just like the 'PageDown' key. If you wanted to delete a non-consecutive number of filters, this was possible with the 'Delete' button, but not with the 'Delete' key, which should be fixed now. The 'Enter' key would close the Filter window, but now the selected filter will be opened for editing. I don't think you will have to use the mouse often anymore.

Version 2.52 (12 October 2008)


  • If more than one groupcall was sent in frame 00/000, there was a slight chance that not all of them would be displayed.
  • When selecting more than one filter in the filter window (using SHIFT), sometimes the wrong filter would be used as the starting point.
  • After copy/pasting one or more filters, the last selected filter would remain selected, instead of the pasted filter(s).

Date format

Besides the date formats DD-MM-YY and MM-DD-YY you can now also select YY-MM-DD. (Options -> General)

Block Duplicate Messages in Filter Window

Once again, a little change regarding this option. It seemed desirable to block duplicate messages in the filter window also. Before, PDW only checked for duplicate messages in the monitor window, which could cause situations like this :

1234567 09-10-08 14:57:49 Message-1
7654321 09-10-08 14:57:50 Message-2
1234567 09-10-08 14:57:51 Message-1

Nothing would be blocked in the monitor window, the first and last message are no duplicate because of the middle one. If you wanted to filter Message-1 (code 1234567), but not Message-2 (code 7654321), Message-1 would appear twice in the filter window. This is solved now, a separate comparison will be made for filtered messages. The only oddity could be that the second instance of Message-1 would appear in het monitor window, but not in the filter window, causing the message to be blocked "partially". However, this change will lead to less duplicated messages in the filter window.

Version 2.51 (16 August 2008)


Mobitex Base-IDs

In the previous version I've made lots of changes regarding Mobitex. Unfortunately, I've made a little mistake in decoding the BaseIDs, causing them to be displayed wrongly. So if you have already started collecting IDs of base stations in your area, I'm afraid that you will have to start all over again :-(

Double mouse click / text selection

With a double (left) mouse click you can now select a word or address, which you can add to the clipboard using CTRL-C (or a right click and 'Copy Selection'), so you can easily paste it somewhere else.

Block Duplicate Messages

Regarding this option, I received a request to only check the message text. Before, PDW compared -if this option was enabled- the current address and message with those of the previous. If there was a match, the second would not be displayed. However, it seemed desirable if only the message text could be compared, so consecutive messages with the same text, but different addresses, could also be blocked.

Next to the option 'Block Duplicate Messages' you will now find 'Only check message text' which will make PDW only check the message text.

Regardless of this change, the option 'Block Duplicate Messages' blocked a bit too much in Mobitex. Messages with the same MAN, but different TYPEs would also be blocked. This would only occur with so-called status messages when the Mobitex option 'Verbose' was enabled.

Mobitex Verbose / Sweep Frames

If the Mobitex option 'Verbose' was enabled, status messages and sweep frames (containing base station information) would appear. Sweep Frames can now be showed apart from status messages. In the Options window you will now find 'Show Sweep Frames (BaseInfo)' next to 'Verbose'.

Version 2.5 (19 July 2008)


In the previous versions I already made the first changes regarding Mobitex. This version contains only Mobitex changes. Not everyone likes to monitor Mobitex, since most data is unreadable. But I discovered that lots of issues were decoded wrongly.


Already in the previous version, I was wondering how the 'messages' were addressed. Every message (package of data) has to have a destination, the receiver has to know what data is his, and what isn't.

Mobitex seems to use MANs (Mobitex Access Numbers), 7-digit numbers which can represent the destination and also the sender. In all previous versions this data was already visible, but was displayed as the first part of the data. This first part is in fact a header, which contains the MANs, datatype, amount of data and can also contain controlling and network information.

Both MANs will now be displayed, along with the data type. This means that I had to get rid of 3 other items, allowing the new items to be displayed. Frame and Bit Sync have been moved to the title bar and you will not find CRC information anymore. On the one hand, the CRC OK/BAD was based on wrong information, sometimes it would show OK when the message contained errors, or BAD when the messages seemed OK. On the other hand, the RX-Quality (F12) should offer enough information about bit- and CRC errors. Also, the RX-Quality for Mobitex has been improved a bit, so it should be more reliable.

Data Types

Mobitex supports 4 different data types :

  • DATA
  • TEXT

By default, they will all be shown. You can enable/disable these items in the Options window (CTRL-O). TEXT should mostly contain readable text, I've never actually seen the type STATUS myself, and DATA and HPDATA mostly contain unreadable data, with sometimes a little bit of readable text. HPDATA stands for Higher Protocol DATA, which allows the user to use their own data protocol. The decimal identification of this protocol (HPID) can be displayed by enabling "Show HPID" in the Options Window.

Mobitex Packets (MPAK)

Like GSM and other cell switched networks, a radio device doesn't only communicate with another device, but also with the network. After all, when switching on a device, it sends a notification, so the network knows that this device is available and via which base station the data has to be sent. These "Mobitex Packets" (MPAK) can be enabled via the Options window.

Controlling / network information

Since Mobitex is two-way traffic, things as acknowlegdements also need to be transmitted. These are very short messages, which also were displayed in a wrong way. I don't want to go into this too deeply, but you can enable this type of information by enabling "Verbose" in the Options Window.

People who already monitor will certainly know the periodic, long and unreadable messages which always seem to contain about the same data. Again, a wrong interpretation, in fact these are so-called "Sweep Frames" which can contain network parameters, or neighbour channel information.

Unfortunately, I don't know the exact meaning of all parameters, but what gets to be shown in the new version comes a lot closer to reality. What also should be displayed correctly are the neighbour channels. Again, like in other digital networks, each base station transmits his neighbour channels once in a while. This offers the mobile stations to periodically check these neighbours to see if one of these signals becomes stronger than the current base station. This prevents the mobile from checking all available channels, which of course takes a lot more time.


Once again, like in other digital networks, each base station transmits its own unique identification. Mobitex uses so-called Base and Area-IDs. These two will be shown in the title bar as one hexadecimal ID. When knowing the exact location of different base stations, this ID can let you know on which base station you are currently tuned. It would be even better if it would be possible to link a name to these IDs, well that is possible! The file base-ids.txt offers the possiblity to enter BaseIDs and a label, such as the location.

Junk at the end of messages

More or less a bugfix, but again a bad (or missing) interpretation. The earlier mentioned headers also contain the length of a message. Since Mobitex data is transmitted in blocks, the last characters of the last block would be filled with junk characters. Now, knowing the exact amount of data, this issue should be solved.

Version 2.4 (16 March 2008)



  • Some advanced soundcards are being listed as two virtual soundcards. One for input, one for output. PDW would display the wrong one (output), but now the input will be displayed
  • Mousewheel scrolling didn't work from all screen positions

Column order

In previous versions the mode/type/bitrate column could be hidden. This option is now replaced by Display -> Screen Options which allows you to enable/disable any column in any order you like. Ofcourse, one column can only be selected once and at least the message column has to be visable.

For FLEX networks which use dynamic groupcalls the options Use "FLEX Group Mode" and "Log groupcodes, but don't show them" can be selected. But as far as I know, dynamic groupcalls are only used in the Netherlands.

PDW Screen Options

Commandfile / commandline

Using the commandfile external software can be called. The number of characters which could be sent through the command line had a certain limitation, but should now be encreased.

Also the commandfile can now be used with monitor-only messages. Before, this was only possible with filtered messages.

2x PDW via the serial port (VXD)

Through the years I received lots of questions if it would be possible to run 2 sessions of PDW via two serial ports. The problem is that a VXD-driver can only be loaded once, on one serial port. It has to be possible to install Slicer.sys more than once, but somehow this also doesn't seem to work. However, someone tipped me that the driver Slicer.vxd (originally used with other software) could possibly be used for the second comport. After some testing this seemed to work, and after renaming it to Comprt2.vxd, PDW would automatically use this second driver if the first (Comprt.vxd) was already loaded on an other serial port. In this way it is now possible to run two PDW sessions using two comports with W98 or ME.


All those years Mobitex didn't change a bit. Recently I noticed that not all characters were being displayed. PDW would skip non-printable ASCII (ASCII-31 and below). In fact, these characters are "non-printable" and shouldn't be displayed, but it seems that these characters are being used differently in Mobitex, causing some messages to be displayed shorter than they should be. In this version these non-printable ASCII is being replaced by other characters so all messages will keep their original length.

Also, the RX-Quality should now be more correct in Mobitex.

Fragmented FLEX messages

Since FLEX messages are being sent in 'frames' (numbered data blocks), there is a maximum number of characters that can be sent in one single frame. If the network needs to send lots of messages at once, it can happen that one message can not be completed in one single frame, causing the messages to be split in two (or more) parts which will be sent in a next frame. If this happens, the message is 'fragmented'.

When receiving such a message on a pager, you normally wouldn't notice this, because in most cases the second part will be received before you are able to read the message. When monitoring with PDW, it would seem that one capcode is receiving more than one message, because the fragmentation-bit is not being displayed.

In this version, some additional information will be displayed when receiving the second (or third/fourth) part of a message, so it is clearer that you are receiving a fragmented message:

FLEX Fragments

Version 2.3 (19 December 2007)


  • Text filtering didn't work correctly
  • Sorting filters by label/description didn't work correctly
  • Already fixed in v2.16, but forgot to mention:
    When monitoring Pocsag, some numeric messages weren't displayed
  • When monitoring Pocsag, biterrors in numeric messages weren't displayed. Also the first alphanumeric characters weren't displayed as biterrors if needed
  • When monitoring a FLEX network with 9 digit capcodes, some messages/capcodes were displayed garbled, or weren't displayed at all (since v2.14!)
  • After adding the new option, which allows the filters in the filter window to be displayed using the same colors as their descriptions, it was difficult to see where a dragged selection would be dropped

Edit filter : + and -

By request I added a - and + button in the Filter Edit Window which allows you to make a quicIn thisk jump to the next or previous filter. You need to push "Apply" first, if you want t o keep the changes.

Using the mousewheel to scroll

Some users could already use the mousewheel to scroll through the received messages. This depended on the mouse driver. For those who couldn't use the mousewheel before, it should be possible now. Also there is a new option within "Scrollback", which allows you to determine the scrolling speed.

Commandfile / commandline

Using the commandfile, users can execute external programs via the commandline. The maximum number of characters which could be used as commandline command seemed a bit too short for longer messages. This limit has been increased to such an extent that I don't expect any more problems.

The commandfile can now also be used for monitor-only messages too. Before, the commandfile was only enabled for filtered messages.

VXD Resets

Now and then I receive reports that PDW sometimes stops decoding after a while, when using the serial port. In some cases, the needle keeps on moving, but no more messages would appear. In other cases, the needle stops and in those cases it would be possible to reactivate decoding by selecting the soundcard, then reselecting the serial port. I tried to detect this "stop" and give PDW an interal reset if detected. If this ever happens, the counter "# of VXD resets" in the Debug Window should keep track of it.

If you ever see any other number than 0, please let me know...

Separate filterfiles

In version 2.15, I introduced "mutiple separate filter files", which allowed you to enter up to 3 separate filter files for each filter. When pusing "more", an extra edit control would appear and the pushbuttons below would move automatically a bit lower. As this didn't always seem to work correctly, all three controls are now visible, but read only. To enter a file, you'll need to select one via the browse button, which also allows you to enter a new filename.

Separate SMTP (per filter)

Since the introduction of SMTP, I received lots of requests for separate SMTP so one can select per filter whether it should be emailed. Finally, this is possible! In the Mail Window (CTRL-M) you'll need to select "Selected Filters Only". Then the "Send Email" checkbox will be enabled in the Edit Filter Window.

POCSAG message types

Sometimes I get reports that some POCSAG messages aren't displayed correctly. The problem is that POCSAG messages don't contain the actual message type. Only the network and the pager(s) both know for sure the correct message type.

According to the POCSAG specifications the function bits should be used as :

  1. Numeric
  2. Tone-Only
  3. Tone-Only
  4. Alphanumeric

Unfortunately, some networks don't stick to these specifications and use the function bits differently, which makes it a bit more difficult to determine the correct message type.

Tone-Only messages will always be displayed correctly, as they are just an "empty message". Also, longer messages will also be displayed correctly, as there is a limit to the maximum number of numeric characters, making all longer messages alphanumeric.

The most difficult messages are those which are shorter than the maximum number of numeric characters, they can be numeric or alphanumeric. PDW uses some tricks to "guess" whether a message is numeric or alphanumeric. In most cases PDW makes the right decision, but unfortunately sometimes a alphanumeric message gets to be displayed as numeric, or numeric messages as alphanumeric.

Some examples of incorrecty displayed messages:

0007210 23:16:45 29-10-07 NUMERIC 1U 5]27830
0600000 22:50:59 29-10-07 NUMERIC 0UU- *64U91 000
0611289 22:52:26 29-10-07 NUMERIC 1U85 00000
0164986 13:14:17 08-12-07 NUMERIC ]3[95[99 161U91 42397 300

0116896 02:01:14 05-11-07 ALPHA   ?n
0115875 02:01:14 05-11-07 ALPHA   E?
0122088 02:01:16 05-11-07 ALPHA   ?"
0115875 02:01:24 05-11-07 ALPHA   !2

Above messages should have been displayed as:

0007210 23:16:45 29-10-07 ALPHA   19998
0600000 22:50:59 29-10-07 ALPHA   0735430
0611289 22:52:26 29-10-07 ALPHA   111
0164986 13:14:17 08-12-07 ALPHA   >>>VOICEMAIL<<

0116896 02:01:14 05-11-07 NUMERIC 41730
0115875 02:01:14 05-11-07 NUMERIC 54900
0122088 02:01:16 05-11-07 NUMERIC 01110
0115875 02:01:24 05-11-07 NUMERIC 12910

One of my (US) users explained to me a bit more about the Pocsag protocol and gave me some tips which allow PDW to correctly display 95% of the messages, which means that only 5% needs to be "guessed". Lots of tests showed that accuracy is now about 99%, which is a huge improvement from the previous version's 90-95% accuracy!

Despite the improved accuracy I added a new option which allows PDW to decode the 4 function numbers as prescribed in the pocsag protocol specifications. In the Pocsag part of the Options (CTRL-O) you will find the new option "Decode function numbers allways as default (1=Numeric 2=Tone 3=Tone 4=Alphanumeric)". Please be sure to know that your network uses the function numbers as 'NTTA', otherwise some messages would be displayed incorrectly after all...

For those networks which don't use the function numbers as prescribed, there is also a new option in Pocsag Options : "If PDW can't make an accurate guess, display message both as numeric and alphanumeric". This will cause messages being both numeric and alphanumeric 100% valid to be displayed as numeric and alphanumeric. Logically, those messages would also be counted twice in the statistics although actually one message was received. Anyhow, in those cases you can be sure that as least one of the two messages is correct :-). When displaying a message twice, they will be 'grouped', using an empty line before and after these two messages, also if the "separate messages" option is disabled.

POCSAG options

Version 2.2 (23 August 2007)


I'm very sorry to announce that from now on PDW doesn't support HTML and FTP anymore. Those options were originally meant to give the PDW users better access to their log files, since plain text files don't support colors and HTML files do. Also, you could access the HTML logging on a local network or on the internet, protected with a password. Nowadays, there are lots of public online PDW monitors which was never my intention. Although PDW users are responsible for republishing paging messages, I decided to end HTML and FTP support.

By ending HTML and FTP support the (public) online PDW monitors will not disappear automatically. I just want to bring to ones attention that public publishing is not really what I had in mind when I started HTML and FTP.

However, who really wants to continue the HTML logging, you could use the external command file. I have ZERO experience with HTML logging outside of PDW, so I can't (and will not) give any support on this particular subject, but it is possible!

Check for duplicate filters

The external program PDW-Filter.exe was written to edit and reorder the list of filters (and some extra options), but when most of these options were integrated in PDW, we stopped PDW-Filter.exe. I received some requests that some were missing the option of checking for duplicate filters, which PDW-Filter offered them. PDW-Filter only compared capcodes, and since you can use more than one filter with the same capcode (but with different text filters), my first thought was that it might be difficult to make a good comparison. Later, I thought of comparing both capcode and text filter. If both are equal, we have a duplicate, and one of the filters can be removed.

In the filters dialog (CTRL-F) you can access this new option with the right mouse button (or with CTRL-O). Only two duplicates at once can be displayed, if there are more than 2 equal filters you'll just have to check again. If PDW finds a duplicate, both filters and their labels will be displayed. Those filters are clickable so PDW can display them in the filter window and you can decide which one has to be removed.

Colors in filter window

Especially when the filters are 'grouped' per user and the label colors per user are the same, I thought it would be nice to display the label colors in the filter window. The background would get the same color as the main PDW background (default=black) and the filter items the color of the filter labels. At first it might look a bit too colorful, but I got used to it myself after using it for a few days. When scrolling, you can see in just a glimpse which user(s) the filters belong to and also if a filter label might have the wrong color.

By default this option is enabled, but if you'd rather not use it, it can be disabled via the Filters window (CTRL-F) -> Options -> uncheck the "Show label colors also in filter window" box.

Just like in the filters window the filter label colors will also be displayed in the filter edit window, in the "Color" box. Again, the background has the same color as the main PDW background (default=black) and the color names will be colored just as their name so you can see in one glimpse what that particular color would look like on the PDW background.

Multiple text filters

I've made up a nice name for this new option which arised out of the changed lay-out of some messages on one of my local paging networks. If you want to filter messages which contain the words "call" and "asap", but these words are not connected like "Call 012-3456789 asap" or "Call the office asap", it wouldn't be possible to filter those messages rather on the word "Call" or "asap".

To make filtering possible on words which don't connect, you can now filter on strings like "call&asap". The &-character indicates that the first and second string can appear separately, but can also be connected. You can use the &-character up to 9 times in one filter, so you can filter on 10 strings at once.

Version 2.16 (01 February 2007)


  • When the filterlist was empty, no filters could be added
  • When the PDW window was being resized, sometimes a message could appear regarding a driver error

Minimize to Systemtray

PDW now offers the possibility to minimize to the systemtray, so it won't be visible anymore in the taskbar. PDW can stay in the tray until you doubleclick the tray icon, or it can restore automatically when a certain message is received.

Via the menu item 'Display' you'll find the Systemtray settings :

System Tray

If you don't want PDW to restore automatically, only select the first option. Else, you can also select the second option and choose one of the 3 options below.

Versie 2.15 (11 January 2007)


  • When using SMTP, the TCP/IP stack would hang after a while, until PDW was restarted
  • When monitoring networks which use a different characterset, and the file language.df is used, the characters would only be remapped on the screen but not in de log files
  • If a complete wildcard filter was needed, ????????? didn't work for 7-digit capcodes. In that case, 00??????? (2 preceding zeros) was needed. Now, ????????? also works

Empty lines between messages

In this version, the option is now selectable for the filterwindow and the separate filterfiles : Options (CTRL-O) -> General.

Before, only the message text was compared to determine if an empty line was needed. Now you can select if you want to check message&time or only the message. Again : Options (CTRL-O) -> General.

This "empty lines option" has also been improved a bit. When using "date log files" a new log file will be created automatically when the first message of a new day is received. In the previous version that new log file would start with an empty line. Also, PDW won't show an empty line on the screen after the screen has been cleared (CTRL-D).

Clear Screen (CTRL-D)

In the previous option I already mentioned 'clear screen'. In this version you can choose whether you want to clear only the monitor window, the filter window of both windows. By default, both windows are selected.


As in almost every update, the CAPCODE.WAV has been changed a bit.
Now PDW uses priorities which allow to 'override' an already playing wavfile :

  1. Complete capcode.wav
  2. Capcode.wav with 1 wildcard (like 000000X.wav)
  3. Capcode.wav with 2 wildcards (like 00000XX.wav)
  4. Capcode.wav with 3 wildcards (like 0000XXX.wav)
  5. Capcode.wav with 4 wildcards (like 000XXXX.wav)
  6. Capcode.wav with 5 wildcards (like 00XXXXX.wav)
  7. Capcode.wav with 6 wildcards (like 0XXXXXX.wav)
  8. Capcode.wav with 7 wildcards (like XXXXXXX.wav)
  9. SoundX.wav (filtered)
  10. Monitor-only.wav

If the priorities are the same, the length of the new file will be used to decide whether the playing file will be stopped. A larger file will have a higher priority and will stop a smaller file.

Filtered messages only in filterwindow

Normally, all messages would be displayed in the monitor window, and the filtered messages also in the filtered pane. Now you can select whether you want to see a filtered message in both panes, or only in the filter window, which causes the 'normal' messages and filtered messages to be fully separated. Filters (CTRL-F) -> Options.

Switching pane sizes (F11)

Via Display -> Scrollback the size of the monitor and filter pane can be defined.
When pressing F11 these sizes will be switched.

SMTP character sets

When using SMTP, you can now select other character sets. Before, a default 7-bits ASCII charset was used, which didn't recognize special characters like "". The default charset is now ISO-8859-1 (West-European).

You can select these character sets :

  • US-ASCII      (Standard)
  • ISO-8859-1   (West-European)
  • ISO-8859-2   (East-European)
  • ISO-8859-3   (South-European)
  • ISO-8859-4   (North-European)
  • ISO-8859-5   (Cyrillic)
  • ISO-8859-6   (Arabic)
  • ISO-8859-7   (Greek)
  • ISO-8859-8   (Hebrew)
  • ISO-8859-9   (Turkish)
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Text filtering at the start of message

Sometimes it can be useful to filter based on text, but only if that text is the first part of the message :

1420076 08:59:55 24-08-06 kunnen jullie een A1 doen?

Sorry for the Dutch example, but on my local network, lots of messages start with "A1". In this example you will find "A1" in the middle of the message, and when filtering on "A1", this message will also be filtered. I added the possibility to add the ^ character before the filtered text, which forces PDW only to filter that text if it is the first part of the message. In the above example, you would have to filter on ^A1 in the filter "text" field.

The ^ character can also be used in capcode.wav file names. In the example above you can use this file name when filtering the capcode '1420076' and text '^A1' : 1420076-^A1.wav

Multiple separate filter files

I received lots of requests for the possibility to define more than one separate filter file. From this version you can define up to 3 separate filterfiles per filter. When adding/editting a filter, you will see the button 'more' next to the separate filterfile. When clicking this button, you can enter an extra file.

Wavfiles only enabled for filtered messages

When using lots of wavfiles, it can sometimes be usefull only to hear files played by filtered messages. Via the option "Filterbeep" you can also enable the sounds for filtered messages only. Just like the multiple edit, this box has now 3 options :

  • On : Filter Beep / Wavfiles (enabled)
  • Off : Filter Beep / Wavfiles (disabled)
  • Greyed : Filter Beep / Wavfiles (enabled for filtered messages)

Version 2.14 (22 June 2006)


  • If "Hide Mode Column" was selected the first message didn't always appear correctly
  • If "Hide Mode Column" was selected with higher screen resolutions, PDW did not always use the full line length, which resulted in messages being cut off before the end of the line
  • When monitoring ERMES sometimes junk / ghost messages would appear

Extra information in titlebar

Normally, the PDW version and current mode would appear in the titlebar. When monitoring FLEX / ERMES it was already possible to see some extra information : the cycles/frames.

From this version, you can select 2 extra options (via Options, CTRL-O), to get some extra information in the title bar :

  • Rejected / blocked messages :


Again, the CAPCODE.WAV has changed a bit. Before, a code had to be filtered if you wanted the capcode.wav to be played. Now this also works for monitor-only filters.

Empty lines between messages

On some networks, more than one ric/capcode gets to receive the same message. PDW now has the option to add an empty line when the current messages differs from the previous message. In this way, all messages with the same text are being 'grouped' and offers better readability. The option "Add linefeed after ALPHA/GROUP messages" can be found in Options (CTRL-O) and can be separately activated for the monitor and the log file. This only works for alphanumeric and group messages.

Soundcard selection

PDW now displays all available soundcards in the Setup (CTRL-S) and the user can select which soundcard to use for data input.


I've received several emails in which people tell me that they are not able to change the font. Actually, this IS possible, but if PDW detects that the characters will become too large to fit in their columns, the change of font is ignored. I can see that users could think that this is some kind of bug, but it is, in fact, protection to ensure maximum readability.

From now on, the selectable font sizes are limited, and when selecting a font size which would cause the characters to become too large, the user will receive a messagebox with a warning.

Font in Filter window

I always thought that the filters in the filter window were a bit messy. The characters used a non-proportional font, which caused one character being larger than the other. This caused not all filters to line up as they should. PDW tried to display all filter options in columns, but that didn't really work out.

Now, the filter window uses a proportional font, so all characters have the same size and all filters line up correctly with all filter options being displayed in 'columns'.

Some screen resolutions caused a horizontal scrollbar to appear in the filter window. Other resolutions caused the filter line to be cut off before the end of the line. Now, in all resolutions, the full line length will be used and "..." will be displayed at the end of the line if the line is too long to display completely.

Also, the current selected filter is being displayed in the titlebar (capcode/label/text).

Multiple Edit

In the filter window, you can now perform a multiple edit. All filter options will be checked, and for example, if all filters are monitor-only, this box will be checked. If some filters are monitor-only, and others aren't, this box will be grayed meaning that it will be ignored when changing the selected filters. You can still check this box so selected filters will become monitor-only.

Tristate checkboxes

In this way, all checkboxes (as well as the colors, sounds and separate filterfile) can ben changed for all selected filters at once. The capcode/labe/text cannot be changed via multiple edit.

Versie 2.13 (27 August 2005)


  • Both slicer.sys and PDW have been updated, because the slicer.sys didn't allways seem to work properly
  • The first digit of StNum messages (in FLEX) was sometimes mismatched

Hide "Mode / Type / Bitrate" column

After some requests it is now possible to hide the column containing mode, type and bitrate information, creating more space for the messages. This option Hide "Mode / Type / Bitrate" column can be found in Options (CTRL-O)

Size filter window

The size of the filter window (CTRL-F) was only fullscreen when using 800x600 resolution. In lower resolutions the window would become to big, in higher resolutions it would be a bit too small. From this version on, the size of the filter window (and the buttons) will be resolution dependent.

Find filter

The filter window (CTRL-F) now contains an find-option. You can enter a search string (capcode or label) and PDW will search in the list of filters for possible matches. When found, you can jump to the next by simply hitting "enter". This Find-option can be found via the button "Find", the right mouse button or CTRL-F in the filter window (yes, twice CTRL-F :) When using the find option in the browser Firefox, I noticed that it already starts searching when typing, and this inspired me to make the same option in PDW. When selecting "Search while typing", PDW will do the same and this option will be saved in PDW.INI for future use.

Version 2.12 (07 March 2005)

Match only EXACT text

I got a request for an option which makes it possible to filter pages only when the filter text exactly matches the received message. Before, you could use the text filter "fire" and filter messages like "fire, please call..". With this new option the message only has to be "fire" before it will be filtered.

SMTP : Multiple email addresses

Now, multiple email addresses can be used. There is no limit for the numer of addresses, but there is a limit of 500 for the number of characters. Since most addresses are about 20 characters long, you can now enter about 25 email addresses. The addresses can be seperated with either , or ;

SMTP : Message in subject/body

It is now possible to choose if the message will be put in the subject, the body or both.

Version 2.11 (20 January 2005)


  • Numeric pocsag messages were sometimes displayed as alpha
  • Filtering/rejecting didn't work well for pocsag and Mobitex
  • Mobitex messages weren't allways received correctly
  • When copying PDW to a CD-ROM to copy the program to an other PC, the files will turn read-only, and the files filters.ini and pdw.ini couldn't be updated anymore

Extra option for capcode.wav

I got a request from someone who would like to use wavfiles for filters which contain a capcode and text. When filtering the code 1234567 and the text "fire", you can use the file "1234567.wav", but from this version on, you can make it more specific by using "1234567-fire.wav". In this way, you can use "1234567-accident" for the same capcode and "1234567.wav" for all messages which don't contain those 2 words.

Version 2.1 (30 December 2004)


  • When monitoring FLEX, "SH/TONE" messages would allways be displayed als TONE-ONLY. In fact, these messages can also contain numeric information.
  • The FLEX phase (A, B, C of D) wasn't allways displayed correctly.
  • When exiting PDW, the XP/W2k driver SLICER.SYS would not allways be unloaded correctly, causing the comport not being able to be used for other software.

Filter window modified

The filter window (CTRL-F) is now only being used for the list of filters. All other options have been moved to a seperate window which can be accessed via the "Options" button.

Default filter type

Via the Filter "Options" button you can define the default filter type (POCSAG, FLEX, etc). When adding a new filter, the default filtertype will automatically be selected.

Logging labels

Logging labels in the monitor-section was already possible, this can now also be enabled/disabled for separate filter files.

Also you can define if the label has to be placed on the same line as the message, or on a new line.

Block duplicate messages

I received some requests for this option. On some networks, the same message seems to be transmitted several times, and if you get to see the message once, that'll be enough. Blocking duplicate messages is only possible if the last message (and capcode) is the same as the current message (and capcode), example :

1. 1234567 Please Call home
2. 1234567 Please Call home
3. 0125447 Call 123-12345
4. 1234567 Please Call home
5. 2255147 Hi, how are you?
6. 2255147 Hi, how are you?

In this example, the messages 1, 2 and 4 are the same. 1 and 2 are adjacent, so 2 will be blocked. Message 4 is the same again, but is being preceded by a different message, so none of these 2 will be blocked. Also 5 and 6 are the same, so message 6 will be blocked. So, in this example the messages 2 and 6 will not be displayed. "Block duplicate messages" can be found in the Options window (CTRL-O).

Wildcards in capcode.wav

It was already possible to define a separate wavfile for each capcode (CAPCODE.WAV), but now you can also define a wavfile for a filter which contains a wildcard. In stead of a questionmark, an 'x' has to be used. Example: The capcode 1234567 is being filtered via the filter '001234???'. The file 1234xxx.wav can be used together with this filter. As you can see, the preceding zero's are not needed.

Preceding zeros are also not needed anymore for the CAPCODE.WAV. When receiving and filtering the code 1234567, the file 1234567.wav can be used. When 1234567 is being filtered via the filter '001234???, PDW will first seek for the code specific file 1234567.wav, if not found, it will seek for 1234xxx.wav, if also not found, the selected soundx.wav will be played.

Rejecting text or capcode+text

After several requests, it is now also possible to reject text strings, or capcode+text. Also, the hitcounter will keep track of the number of hits (and time/date of the last hit) for rejected filters.


Some FLEX paging networks broadcast the 'FlexTIME', which contains the current date and time, which can be used by the pagers, so time and date don't have to be set manually. It took some time to discover the FlexTIME format, but we did it. From this version on, the FlexTIME can be used to correct the PC systemtime.

This option can be found in the Options window (CTRL-O). First, PDW has to detect the FlexTIME. If not detected, the option will be disabled. If the option stays disabled, the FlexTIME is apparently not being used on that particular network. If used, the option can be selected and the system time will be checked/adjusted every hour.


One of the new options in the previous version was "monitor_only.wav". One sound for alle messages which are being filtered as monitor-only. This sound can now be enabled/disabled for each filter. Default, the monitor_only.wav is disabled. If you were using this sound, you'll have to enable this 'new' option for all desired filters.

Version 2.0 (10 November 2004)


  • Filtering of capcode+text didn't work as it used to


At last, we can offer a driver for Win2K / XP.

Use "install.exe" to install the "slicer.sys" driver. Reboot, and the comport can be used! Unfortunately this driver doesn't work for the NT operating system.

Filters / PDW-Filter.exe

The program PDW-Filter.exe was written to edit and reorder the list of filters, but from this version on, all extra options are added to PDW. Using the mouse, filters can be dragged/dropped. CTRL-A can be used to select all filters to sort them by capcode or description (right mouse button). CTRL-C & CTRL-V can be used to copy a filter, these options are also available via the right mouse button. When copying a filter, the hitcounter can be reset to start counting over again.

Label colors

The number of label colors has been extended to 16.

Label variables

Some paging networks are used by public safety. In some cases, the last digits of a capcode are similar to the number of the ambulance/firetruck which is being paged. On the Dutch P2000 network the last 2 (or 3) digits mostly match the ambulance number. In this case, it could be useful if a single filter with wildcard can be used, and the last digits being placed in the label. To do this, make a filter like :

Capcode : 10230?? (wildcard) , Label : "Ambulance %67"

When receiving a page for capcode 1023024, you will get this label :

"Ambulance 24"

The digits following the '%' represent the positions within the capcode which have to be placed in the label. The 6 and 7 in this example represent the last 2 digits : 24.

Pane sizes

Before, there were only 3 selectable pane sizes, 35%, 50% and 65%. Now you can enter all values between 20 and 80%.


Again, we fixed some minor ACARS bugs, the layout has been improved, updated df-files are available, and PDW can also provide some extra information on the flight-route, using 'routes.df'.

It is also possible to filter on registry numbers.

Month numbers

I received some requests regarding the name of the log files. If they are completely numeric, the order will always be 'correct' when sorting by name. In Options (CTRL-O), you can select "use month number for log file names".

Directory for log files

By default, the log files will be placed in the directory "log files". This directory can now be changed via Options (CTRL-O).


I thought that it could be useful to hear a sound when a Monitor-Only page is being received. Not a selectable sound, but one sound for all Monitor-Only filters. When a message matches a Monitor-Only filter, PDW will play "monitor_only.wav", which has to be placed in directory "Wavfiles". If not found, no sound will be played.

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