I have a problem that I'm pulling my hair out and hope someone can give me some advice.

System:
Quadro 6L with V5.2.11 application software.

There are 6 PSTN ports connected to each of the FXO ports.
There are 8 Polycom 550 phones on the network.

The customer reported periodic complaints that when a person selected an extension from Auto Attendent that had been forwarded to an outside line they would get an error message from the PSTN saying that "Were sorry you must first dial a 0 or 1 and then the area code when dialing this number"

The PSTN requires all outgoing calls to dial 1+NPA+NNX+QRST.

If the outgoing call forward goes to FXO port 0 or 1 the call goes through without an error.

If the outgoing call forward goes to FXO port 2-5 the call fails with the error message.

NOTE it only fails on those ports when the call is from a phone that has been forwarded. The user had entered the call forward number on the Polycom phone.

You can place calls outbound on port 2-5 if you dial direct by entering 9+1+NPA+NXX+QRST on the phone. Works great.

It sure looks like the PBX is sending the DTMF digits before the phone line is ready to receive them.

I've been looking through the documentation and FXO configuration to find a way to extend the wait time before sending the DTMF digits.

I also did a FXO Diagnosis and set the configuration to the recommended CSRS setting. Didn't correct the problem.

I also looked to see if Call Routing could offer a solution, but couldn't create a rule that would work for call forwarding from the AA.

I have to believe that someone else has run into this situation and would appreciate your guidance. Thank you in advance.