7.12.4.2 Dialing From Pbx Line Or Pstn; 7.12.4.3 Message Waiting Indication For Remote Extensions - AudioCodes MediaPack MP-124 User Manual

SIP User's Manual

7.12.4.2 Dialing from PBX Line or PSTN

The procedure below describes how to dial from a PBX line (i.e., from a telephone directly
connected to the PBX) or from the PSTN to the 'remote PBX extension' (i.e., telephone
connected to the FXS device).
To dial from a telephone directly connected to the PBX or from the
PSTN, take this step:
Dial the PBX subscriber number (e.g., phone number 101) in the same way as if the
user's phone was connected directly to the PBX. As soon as the PBX rings the FXO
device, the ring signal is 'sent' to the phone connected to the FXS device. Once the
phone connected to the FXS device is off-hooked, the FXO device seizes the PBX line
and the voice path is established between the phone and PBX.
There is one-to-one mapping between PBX lines and FXS device ports. Each PBX
line is routed to the same phone (connected to the FXS device). The call disconnects
when the phone connected to the FXS device is on-hooked.

7.12.4.3 Message Waiting Indication for Remote Extensions

The device supports the relaying of Message Waiting Indications (MWI) for remote
extensions (and voice mail applications). Instead of subscribing to an MWI server to
receive notifications of pending messages, the FXO device receives subscriptions from the
remote FXS device and notifies the appropriate extension when messages (and the
number of messages) are pending.
The FXO device detects an MWI message from the Tel (PBX) side using any one of the
following methods:
100 VDC (sent by the PBX to activate the phone's lamp)
Stutter dial tone from the PBX
MWI display signal (according to the parameter CallerIDType)
Upon detection of an MWI message, the FXO device sends a SIP NOTIFY message to the
IP side. When receiving this NOTIFY message, the remote FXS device generates an MWI
signal toward its Tel side.
Version 5.4
Figure 7-10: MWI for Remote Extensions
345
7. IP Telephony Capabilities
May 2008