Batboard

So I've recently started to build the right cable for interfacing a VHF M1225 with a Vertex VXR1000U vehicular repeater. I've dealt with the fun of a Maxtrac 16 pin connector before so I figure this would be a walk in the park for but it's not. I've used the application notes from Pyramid as my starting point for wiring and configuration but I seem to just can't get each radio to do COR and PTT correctly. If I force PTT by hand I do hear repeated audio so I know some of my work right.

I'll post my wiring and programming notes when I get a chance but does anyone have any advice trying to get the interface right?

Dont know if this helps or not, you probably have it already but doesnt hurt to post it for reference

verify your programming in the VXR is correct and the solder in jumpers on the VXR are correct. I have a few of these in service and have no issues at all. You should be able to take one from a maxtract, 1225, CDM and they all work the same.

Yeah I have looked at the service manual and I think in trying to translate the Pyramid notes to the VXR, I got things screwed up in the process.

jsikora: do you have notes on the right wiring and prgramming I could compare? I'm at the point where I need that.

KE7JFF wrote:Yeah I have looked at the service manual and I think in trying to translate the Pyramid notes to the VXR, I got things screwed up in the process.

jsikora: do you have notes on the right wiring and prgramming I could compare? I'm at the point where I need that.

If I get home tonight at a reasonable hour i'll dig around. the picture above of the VXR wiring outputs is all you really need and the pinout from the maxtract mobile 16 pin. I normally use pin 8 or 14 for COR from the motorola. Make sure the vxr is set for COR Low activate. Same with the ptt line from the vxr needs to go low on PTT. I have set up numerous of these for our SAR folks and have no issues at all. I actually have set up a couple back to back as a cheap interop V/U repeater.

jsikora wrote:

KE7JFF wrote:Yeah I have looked at the service manual and I think in trying to translate the Pyramid notes to the VXR, I got things screwed up in the process.

jsikora: do you have notes on the right wiring and prgramming I could compare? I'm at the point where I need that.

If I get home tonight at a reasonable hour i'll dig around. the picture above of the VXR wiring outputs is all you really need and the pinout from the maxtract mobile 16 pin. I normally use pin 8 or 14 for COR from the motorola. Make sure the vxr is set for COR Low activate. Same with the ptt line from the vxr needs to go low on PTT. I have set up numerous of these for our SAR folks and have no issues at all. I actually have set up a couple back to back as a cheap interop V/U repeater.

Ahhhh! For some reason I thought I read to set everything to COR High! No wonder! Once I get back to my bench I will change that over.

NOTE:

Motorola does not call it COR, it is PL/DPL Detect. Also know as RUS, receiver un-squelch. A combination of PL/DPL Detect AND receiver un-squelch.

In the M1225 this signal is a low going signal on the accessory pin. You will need a pull-up resistor, about 4.7K ohms works well.

No internal mods are required in the radio, it is all on the accy connector.

Will wrote:NOTE:

Motorola does not call it COR, it is PL/DPL Detect. Also know as RUS, receiver un-squelch. A combination of PL/DPL Detect AND receiver un-squelch.

In the M1225 this signal is a low going signal on the accessory pin. You will need a pull-up resistor, about 4.7K ohms works well.

No internal mods are required in the radio, it is all on the accy connector.

Yeah, I know it's called RUS but its just easier to call it COR among us radio folk. I've never heard of the resistor required on the M1225 and I have interfaced the radio before to other devices.

KE7JFF wrote: I've never heard of the resistor required on the M1225 and I have interfaced the radio before to other devices.

The pull-up resistor is usually in the device the radio is interfaced to... The VXR in your case.

VXR has a jumper for the resister. No additional items are needed. 1225 will go low and the VXR will key if the jumper is correct.

Okay, I got everything back on the bench and still not working correctly.

I've verified all settings are now low. Now, looking at the manual for the VXU, I don't see where the right jumper for the 4.7K resistor is; I do see mention of it for the audio but thats already set. It sounds like I need to put in my own pull up resistor? Am I reading that right?