The Commtel COM217 is a fairly recent scanner. It's almost identical to the Albrecht AE-66M and the Uniden Bearcat BC700A.

The receiver IC is an MC3361 and is located at the solder side of the circuit board. The unfiltered audio can be found on pin 9.

Commtel COM217

The location of the receiver IC

The components soldered to pin 9

Follow the next steps to make the discriminator output:

• Solder a 10 k resistor to pin 9 of the MC3361
• Connect a 2.2 nF capacitor to the resistor's other lead. The other lead of the capacitor is connected to a grounded solder joint on the circuit board
• Install a 3.5 mm mono socket in the scanner's back
• Connect the resistor/capacitor junction with the signal solder lug of the chassis socket (red wire). The wire can be led to the component side at the back of the scanner.

The housing is connected to ground, so the chassis socket is grounded as well.

The chassis socket in the back of the scanner