Call transfer using Hookflash on 53xx phone

[JeremyJGW]

Hello everyone, I am working with a client who is experiencing heavy echoing once an outside caller is transferred to an extension or public number. The operator let me know that in the past one of the phone techs showed her a procedure to use a hookflash softkey to perform a transfer which reduced the echoing symptom.

I have been unable to successfully transfer using a hookflash, the procedure I found states to press the hookflash button, wait for double dial tone sound, dial your intended number then hang up to transfer the caller. In practice this is not working. I press hookflash, get one beep and dial tone, then when I dial an extension or DID the display just shows an error, I can hookflash again to get back to the caller, or hang up and the call will ring back in 5 seconds.

Is anyone familiar with this method of transferring calls on a MiVO 250 system that can fill in the gaps in my process?

[acejavelin]

Sounds like it is trying to do a CO Transfer... used with analog POTS CO lines that have the transfer feature from the telco for those lines. You send a hookswitch flash on the line, get a second dial tone (usually a dat-dat-dat-daaaa), dial the destination (external, no DID or extension) number, then disconnect to complete the transfer. You could test this with a buttset on the trunk itself to see if the telco has this feature enabled or not, but it sounds like they don't have that feature enabled.

This only works on analog POTS CO lines with the feature enabled from the telco... It won't work on PRI or SIP trunks

[JeremyJGW]

That explains it then, I just found out the Telco switched them to a PRI an unknown time ago, they are using a ATA in reverse to break the PRI into 5 analog lines that are fed into the controller so I have done all my troubleshooting assuming analog lines to the telco.

Thank you for the reply

[acejavelin]

If the gateway is configured properly and the telco supports 2 B-Channel Call Transfer (TBCT) it should still work, but a lot of telco's don't support this and even if they do, then their gateway needs to be provisioned properly to handle it. Honestly, this is rarely worth the hassle if the telco doesn't know what they doing.

Make sure you setup and do your Hybrid, ERL and Loss testing on the analog lines... this will likely eliminate the echo issues.