SIP phone: Forward unattended call
From Zenitel Wiki
The Event Type 33 - Private Ringing Outgoing can be used to forward unattended SIP calls. In order to work, it requires that the SIP device returns the SIP status "180 Ringing" when the phones starts to ring, and "200 OK" when connecting.
The forwarding function has been verified with:
- IP Dect System 6000
- Grandstream GXP2000
- Cisco Call manager 6 with Cisco IP Phone 7960
- Alcatel OmniPCX (OXO) via SIP trunking
- Ascom IP Dect System
Note - The event type 33 require AMC 10.30 or later.
AMC10.55 and later
- The SIP phone is 9555.
- When an intercom station calls 9555, the phone will start to ring, the ringing time is controlled by the "Private Ringing Time" timer (30 sec default). If not answered, the call will time out, and the event 33 is triggered. This event sets up a new call to directory number 9547 (which can be an intercom or another SIP phone).
- $C is needed to "speed up" the disconnection, so that the $DD command is not lost during the disconnection tone