Cisco DCE Adapter for P25 STUN Connection to Quantar

In order to connect a Motorola Quantar to a P25Reflector for P25 operation I had to setup a new system for testing purposes. To connect the Quantar to a Cisco router for STUN encapsulation one normally used a Cisco V.24 DCE cable with an adapter to RJ45 on the Wireline card of the Quantar ([1]).

During placing an order with Mouser Electronics I identified the 60pin LFH connector manufactured by Molex by random. The idea was born to directly homebrew a nice cable to connect the RJ45 plug on the wireline board to the Cisco router.

Homebrew Cisco DCE Quantar Adapter

While discussing on a P25 group Tobias OE9TEV added the idea to use an SubD15 to RJ45 case for that so that a common LAN cable could be fitted in between. So I disassembled a Cisco cable and measured all pins on the V.24 DCE cable.

Adapter pinout

The pinout is shown in the picture above (Sorry, no KiCad drawing due to missing footprint of the Molex LFH connector). I used part number 636-RJADK15P7080821 as case ([2]). The colors apply to this case. YMMV. Some pics of the inner details at [3].

References

[1] https://www.qsl.net/kb9mwr/projects/dv/apco25/IP%20link%20Quantar%20V.24%20systems%20using%20Cisco%20routers%20V2.pdf
[2] https://www.mouser.de/ProductDetail/636-RJADK15P7080821
[3] https://twitter.com/flo_0_/status/1161284478423228417?s=20