I have a customer who has an ATA 187, they have connected an RJ11 to RJ11 cable between the ATA and an analgoue phone (directly into the back of the phone), however are not getting Dial-tone. I believe the cable in use is a straight-through cable using all PINs.
Can someone please confirm what pins are used and if there should be any cross overs within the pinouts? A link to an example cable would be helpful.
The only pair/Pins that matter on an FXS port like the ATA187 provides
are Pin 3&4 (Tip and Ring). This type of analog device is unlikely to be polarity
sensitive so using a straight-through or cross-over cable shouldn't matter as long as
pins 3&4 are carried across On most "silver satin" line cords 3&4 are the
blue white/white blue pair or sometimes green/red.
Thanks for the reply - I am going to site next week to experience first hand but something is strange, I believe the cable is pushing through all pins straight through, however there is no dial-tone when using RJ11 in the ATA and RJ11 in the Phone.
If the customer daisy chains the new cable (RJ11 to RJ11) with the existing cable that comes with the analogue phone (RJ11 to BT plug) they do get dial tone and can make and receive calls, but there is a lot of noise on the line.
Also just noticed - If I take my PC Modem Cable (RJ11 to RJ11 - then a Modem Socket Adapter RJ11 to BT Plug Convertor) I get dial tone from my PC, however if I plug the RJ11 into the back of my phone I do not get dial-tone.
So looks like there are different type of wiring for RJ11.
RJ11 is a standard but it looks like BT does something with their wiring that does require
a part like the one you nicely noted +5
It looks like the BT end is called a BT431A and the pinouts are quite different