Kenwood V71A and RA-40 controller

[kb7kwk]

Has anyone used a RA-40 controller? I am looking for steps on how to wire it up for Allstarlink using a Kenwood TM-V71. I find mention of here and other sites but no one ever shows how they did it. I would think it would be fairly easy but I am not having any luck. I wired the mic plug for the normal stuff and I thought that the COR would come from pin 6 on the mini din data plug on the back of the radio. I am missing something.

[wd6awp]

I’m not familiar with the TM-V71 or the RA40 but a couple of thoughts. Check the https://www.masterscommunications.com site if you have not already. The other thought is maybe the COR line needs a pull-up?

@kuggie checks in here regularly. He or someone can help better than I.

[k8zgw]

I have “played” with a couple of the Masters Communications RA-xx
devices, they are sometimes a little confusing as in some cases you have to turn your thinking around. Other then that we have no problems with them.
The 9 pin is some standard, as other RI’s use the same pin outs.

[kuggie]

Pin 6 of the radios DIN-6 connector can connect directly to the COS (or CTCSS) input of the RA-40. You never need a pull-up on any of the C-Media chipsets for these logic inputs to work correctly. Here’s a dissertation as to why:
https://www.masterscommunications.com/products/radio-adapter/logic-inputs.html

You may want to also look at the DRA-50. It’s designed to connect directly to radios like the Kenwood TM-V71A with a simple/cheap male-to-male Mini-DIN-6 cable.
https://www.masterscommunications.com/products/radio-adapter/dra/dra50.html

The schematic of the DRA-50 should give you a clue as to the connection, but pin 6 of the radios DIN-6 will need wired directly to the COS logic input and then will work the same no matter what RA, RL, or DRA you have.

Kevin W3KKC

[N4LPK]

I believe the V71A has to be set in 9600 baud to get the right pin configuration out of the Mini din connector.

[Brett_Friermood]

All applicable outputs and inputs for remote use of the V71 are available via the rear 6-pin mini-DIN connector, including COR.

Here is a previous post I’ve made about connecting to a V71 with a few more details:

Un-encoded pl transmissions breaking squelch

First, verify which pin you are using. On the 6-pin mini-DIN connector there are two audio output pins available: Pin 5 “PR1” which is meant for 1200bps packet applications, and Pin 4 “PR9” which is meant for 9600bps applications. The circuitry in the radio is different for each due to their intended applications. This is a voice application and should be using Pin 5. Secondly, make sure the settings in the radio are correct. It appears you are familiar with the Data Band menu item. This obvio…

[Brett_Friermood]

Actually I would say the 1200bps setting is more suited for voice use.

The audio output voltage changes with the speed selection, as well as the pin, although both are available on the 6-pin connector. Another, unconfirmed, change may be the absence of proper channel activity output when using the 9600bps setting.

I am interfacing to a V71 via the 6-pin connection in an application alongside commercial Motorola radios. I chose the 1200bps selection as the audio voltage level matched that of the Motorola radios. With that setting the Rx audio level seen by downstream equipment nearly matches that of the other radios. In addition I see a valid channel activity signal whether the radio is receiving carrier squelch, CTCSS or DCS, or AM transmissions.

I intended to do some testing to confirm the presence of a channel activity signal with the 9600bps setting, but I don’t think I did since it was working as designed at 1200.