We have several NEC IP Phones and a few Grandstream ATA Adapters for fax machines and analog devices. Before a recent firmware upgrade to 8.00.00, everything was good. After the upgrade, a few of the Grandstream devices have been having issues. The first one seemed to be resolved by re-assigning a different IP address to the device. I spent half a day troubleshooting, swapping extensions, replacing the adapter with a new one, checking for IP conflicts, etc. Of course, the last thing I tried was changing the IP address and it started working and has been solid since.

However, this other Grandstream ATA that goes to a DoorKing gate phone. Before the upgrade it was fine. After the upgrade, anytime it dialed a NEC VoIP, it the NEC VoIP would ring, but the ATA would received a busy signal. When the NEC VoIP went off-hook, it would hang up and drop the call. Using the Grandstream ATA, I can tell the DoorKing to dial a SLT/MLT, an off-prem phone or even a cell and it works. But since the upgrade, that one adapter will not work when dialing a VoIP phone.

I remember from class a few years ago, an article ID 11373 - VoIP Terminals Receive Busy Then Hang Up When Going Off Hook to Make or Answer Calls (Published in 2014). It talked about licensing in 10-54-01, but that's not my issue. I've got license for 150 IP phones. I'm really thinking this has something to do with the firmware upgrade. We've replaced the ATA, moved extensions, changed IPs, replaced the DKS dialer, etc...nothing seems to work. Suggestions?

I would reset all the switches. It's possible the ARP tables did not update. Also, are you using VPN and or NAT remote?

Coral,

Sorry for such a delay, but thanks for the reply. Yes, I've reset the switches all the way to the core. The ARP tables look good. There is no NAT or VPN. These devices are on the same subnet as the server and phones. They are on a completely isolated network with it's own set of physical switches and fibers.

Have you gone into 90-23 and then have it add back in? Have you also checked that some sort of forwarding wasn't activated?

Yea, I've completely deleted the extensions all the way to the System Numbering level and recreated them on different ports. I can have the analog line dial any VoIP and get the same results. I've replaced the ATA adapater and that didn't fix it. I also changed the ATA Adapter with a known working one from a fax line. The both analog lines work when the adapters were switched, but I still could not call out from that that particular analog line. Thought it might be the ending equipment/dialer, but I put a plain telephone on it and still resulted in the same behavior. The only two things I've can think of is 1) the firmware created an issue and possibility affected some sort of sensitivity with that line; 2) there was a hum on the line before the upgrade and after. I'm just wondering of there is a sensitivity setting someone that has been added or changed with the firmware.

Have you put these on a workbench on the same switch as the system and tried that? Almost sounds like a DTMF payload setting on top other things.