User's Manual 30. Analog Gateway
Version 6.8 507 Mediant 500L MSBR
Analog phones (POTS)
PBX (one or more PBX loop start lines)
LAN network
30.14.1 Dialing from Remote Extension (Phone at FXS)
The following procedure describes how to dial from the 'remote PBX extension' (i.e., phone
connected to the FXS interface).
To make a call from the FXS interface:
1. Off-hook the phone and wait for the dial tone from the PBX. This is as if the phone is
connected directly to the PBX. The FXS and FXO interfaces establish a voice path
connection from the phone to the PBX immediately after the phone is off-hooked.
2. Dial the destination number (e.g., phone number 201). The DTMF digits are sent over
IP directly to the PBX. All the audible tones are generated from the PBX (such as
ringback, busy, or fast busy tones). One-to-one mapping occurs between the FXS
ports and PBX lines.
3. The call disconnects when the phone connected to the FXS goes on-hook.
30.14.2 Dialing from PBX Line or PSTN
The following procedure 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 interface).
To dial from a telephone directly connected to the PBX or from the PSTN:
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.