We don't sell many CP-135 / CP-136 for new Audio Panel installations, nor do we recommend them for this application. But if you need a slide-in replacement, a CP-135 and/or CP-136 may be worth considering. (It is disproportionately expensive to install an Audio Panel because of all the wires that come together.)
The CP-135 and CP-136 are physically interchangeable.
The difference between the CP-135 and CP-136 is an Audio Amplifier. The CP-136 is able to power a cabin speaker, and the CP-135 is not.
If a CP-135 is replaced with a CP-136, the installation will not utilize the CP-136's amplifier as wired, and the speaker will not be powered. (It would require some additional connections to use the amplifier.)
If a CP-136 is replaced with a CP-135, the cabin speaker will no longer be powered.
For either the CP-135 or CP-136, the "M" suffix means Marker Beacon Receiver. The CP-135M and CP-136M have an internal Marker Beacon Receiver. The CP-135 and CP-136 are able to use an external Marker Beacon Receiver, but they do not have this receiver built in.
Narco's CP-135M combines both an Audio Panel and Marker Beacon Receiver in a compact unit. (The "non-M" version does not include the marker section.) Despite its small size, the CP-135M uses large pushbuttons to positively select the audio source. It also features a marker audio muting control and High / Low marker volume. A test function verifies that the marker section is working properly.
Some of our CP-135M's, like the one pictured here, have a refurbished face plate and look very clean. These are used avionics that don't look used up!
The CP-135M has the following switch positions:
- 2 COMMs
- Both (COMMs)
- 2 NAVs
- Marker Beacon / DME