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Community Member

No ring on an analog phone


Tochiba Decade PBX fxs port conneted to a 2610xm cisco router on an FXO port.The router is connected to WAN. On the other end we have 1751V with FXS ports. The problem is that remote users connected to FXS port do not hear a RING when the users at central site call them through the PBX.

If they pick up the phone, they can talk, but NO RING?

if i connect the FXO port at central site to a POTS line, everything works fine.

Anyone had a similar issue?

any suggestions would be highly appreciated.



Re: No ring on an analog phone

do you have a "progress_ind setup enable 3" command on your dial-peer on your 2610?


Community Member

Re: No ring on an analog phone

I Found the problem,

The card on the toshiba PBX is an old one, it is supplying -24V of voltage and has a credence of 1sec on and 3 sec off. The problem is that the cisco routers support -48V voltage on FXO ports and have a cradence of 2 sec on and 2 seconds off.

I know that the cradence valuse can be changed, but what about the volatge? can be pump up the voltage, the PBX can not do it.

any suggestions?


Re: No ring on an analog phone

You can't make the FXO port more sensitive. The low loop voltage should not make a lot of difference, but there is probably a matching low AC ring voltage which is not enough to trigger the FXO port ring sense circuit.

Progress_ind commands will not help here as they are for ISDN connections - this is an analogue port.

Use a line extender to boost the level from the PBX. Here is a suitable unit -

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