HT-503 behind an analog PBX

[hacktek]

So this is kind of weird but bear with me here. We are trying to have a controlled test of VoIP and 3CX with a small group of people using an HT-503. I've gotten it to register with 3CX and have been able to do internal voip calling just fine. The problem is going outside.

The analog phone is plugged into the HT-503 and the FXO port goes into the wall jack, which then goes into an Analog PBX, like so:

SIP phone<->3CX PBX<->HT503<->analogue PBX<->PSTN

Without the HT we have to press 9 to get to the PSTN. With the HT we have to press 9 to get to the PBX and then 9 again to get to the PSTN.

The most i can get to is to the analog PBX (by calling 9 with the soft phone, i see the "phone" light go on in the HT) but i cannot reach the outside world. I would imagine this should be possible, i just need a push in the right direction.

In the log i get mostly 403s when i attempt to reach the PSTN.

Thanks

 

[leejor]

It very well may be a dialplan problem, but, connecting to a PBX rather than a POTS line can present additional issues. Most ATA's are defaulted for a POTS line, they expect to see about 48 volts DC when the line is idle. If the voltage is lower , like 24 VDC that some PBX's put out, then the ATA thinks the line is in use and won't put the call through. That is usually a setting you can change in the ATA. The other problem is that some older PBX's require that you wait for a second dialtone before dialing the outside number. If you send the whole number, 9 and all, at one time,as the ATA will, the board will miss a few digits and the call will fail.

 

[hacktek]

Thanks for your response leejor.

I have verified that the analog pbx at work dials when the entire number is sent out at once, it can be easily verified by dialing out (9+number) and then trying to call again using "redial" on the phone. It works fine.

I know that this is a strange setup but i can't do it any other way since i cannot get rid of out analog pbx just yet.

Thanks

 

[leejor]

It would probably help if you posted a 3Cx log of the attempted outgoing call.