Digicom/Telex Crossover Intercom

[clmiller24]

I have a telex wired system with BP-1002s. I have a wireless digicom (porta phone) 900Mhz coaches system. I want to use the two of them together. I talked with eartec, and they are phasing out the porta phone line and wanted to move me to the new line. We are a middle school production and with only doing three shows a year, cannot justify spending that money on a new system. Anyway, I think i have it figured out, but wanted to see if anyone could give some input.

Telex and Digicom both use the same headset 4pin XLR connections: P1- Headset Mic Low, P2- Headset Mic High, P3- Headphone high, P4-Headphone Low.

I was thinking of doing this:
headset line on TE -> headphone line on DI
headphone line on DI -> headset line on TE

I know one problem:
SIDETONE. On the telex unit, they have a sidetone adjustment, I can drop the sidetone DOWN the entire way. I need to see if the digicom unit has a SIDETONE adjustment. This is my biggest worry, because if I cannot adjust the SIDETONE, than I believe I will be adding a feedback into the system.

Would I need to make any other adjustments? Add resistors into the system cable? I am great with following wire diagrams, so I can make/solder anything together.

Any help would be greatly appreciated.

-clm

 

[Stookeybrd]

Telex and Digicom both use the same headset 4pin XLR connections: P1- Headset Mic Low, P2- Headset Mic High, P3- Headphone high, P4-Headphone Low.

I was thinking of doing this:
headset line on TE -> headphone line on DI
headphone line on DI -> headset line on TE

I cannot find any manual or tech sheet for the Digicom that provided useful information, but the short answer is not easily. The signal strength coming from the headphone outputs is going to be much stronger than the anticipated current of a microphone. Without know anything about the circuitry of the Digicom a good place to start is assuming that is line level and dropping it to mic level in both directions and work from there. Here is my favorite explanation on how to do so. Beware, there is no guarantee that this will be the correct solution. I don't know what type of mic inputs either pack is able to handle, or the strength of the headphone output.

As far as the sidetone, you are correct in wanting to remove it from the crossover belt-pack entirely. If set high the sidetone will be taking the Digicom's output and then reinserting it into the Digicom input. Could end up being unnoticeable at very low levels but could also make the system unusable.