Is it possible for a Cisco ATA 186 to work off a Meridian 1 Opt81C PBX using H.323?
H.323 device←H.323→CiscoATA_FXS←Analog→Nortel Meridian FXO
It seems that you're making a call through the Nortel Meridian, perhaps from a phone set. The Meridian FXO line goes off hook and dials into the Cisco ATA but the ATA returns a busy tone.
One basic problem could be that the Nortel DTMF level cannot break the dial tone on the ATA.
You can use a network Sniffer, such as Ethereal, to see if the ATA 186 collects all the digit information from the Nortel and sends this out properly on the Ethernet interface.
If a gatekeeper is being used in the H.323 network, one of Cisco's web pages mentions a problem to look out for.
This was first published in March 2006