Studio Expansion microphones (Longer cable)

[povallee]

Hi,

We've purchased the Expansion Microphone (2200-69631-001) that can be connected with the Polycom Studio. In the box there is a RJ-12,  24 ft long cable that came with it (2457-69573-001) but because of our installation the cable is not long enough. We had a 50 ft RJ-12 cable in stock so i've tried this cable but for some reason it doesn't seems to work. The cable pin out seems to be the same but there is no power going into the expansion microphone when we are using our own cable. We've tested the cable with a cable tester and the cable is good.

I was wondering if there is any specifications available about the cable use to connect the Studio to an expansion microphone ? I'm looking for details about the cable pin out, shield requirement, cable max lengh but I couldn't find anything online. Any idea where i could find this information ?

Thanks

[povallee · Accepted solution]

For those interested i've received the following information from our rep:

Polycom is not using normal cable for Debut  Micpod, it’s customized 

1. Wires 1, 3, 6 for microphones are specially shielded for voice transmission quality  
2. The outer shield – the invisible 7th wire – is used as GND signal. 

If other 6P6C cable is used, it might work if with luck. But typically the voice quality might be impaired (reason 1) or it just doesn’t work(reason 2).