Our Motorola 16 pin harness to IRLP -  $38 US

While various IRLP plug and play cables are available for purchase online, I have decided to toss mine in the hat for public consumption. For several years I have been successfully using this design for the Motorola links to our various IRLP nodes and have engaged Kurt WB9KNX to assemble them - at what I feel is a terrific value, given his crafty workmanship. 

The 36" harness has a user accessible DB9 male instead of a hacked molded serial cable, so that you can make modifications or add features to in the future. It also makes for easy repair or diagnostic access if you should have a problem suspect. 

Two 14" audio leads for transmit and receive audio to the sound card use stereo plugs whose tip and ring are already combined to a single path going to the radio. One cable is marked as RX audio, which is the radio's receiver going to the line in of the sound card.  The DTMF audio sense also is tied here in the DB9. 

A 10uf non-polar capacitor has been inserted into the transmit audio path to block the DC voltage from the radio - that often interferes with some sound card op-amp output circuits. 

Four 6" flying leads are available at the radio end that - terminate to the IRLP board's Auxiliary Outputs 1-3 on the DB9. An extra lead has been made available to provide a convenient logic ground. Many folks choose to use the aux lines to activate PA fans, change PL enable/disable states, disable the PTT for a listen only mode, change channels that may include a different PL tone, trigger a CWID board, repeater controller functions, tight squelch... etc., the sky's limit with many clever scripts available. You may never use the aux lines, but they are there if you choose to put them to use.

The internal speaker jumper is in place, so that you can monitor the radio locally. We find that folks that have nodes in their homes or place of business can use the link radio (with a local mic) to conveniently talk to their repeater, while the node is idle. Since the speaker volume is independent of the IRLP audio feed, it can be safely turned down without affecting IRLP levels.

We offer the cable - tested and ready to plug and play for $38. No purchase of a radio is necessary if you would like one. The harness is designed for the version 3 IRLP board but will work with the older V2.01 and V2.02 boards as well - without the use of the aux lines of course.

 

 

Please do not distribute or repost schematic diagram without permission !
The design is subject to change.  Thanks, KD4RAA