AudioCodes Mediant 800 - Dialing from PBX Line or PSTN; Dialing from Remote Extension (Phone at FXS)

CHAPTER29 Analog Gateway
Mediant 800 Gateway & E-SBC | User's Manual
This section provides an example on how to implement a remote telephone extension through the
IP network, using FXO and FXS interfaces. In this configuration, the FXO device routes calls
received from the PBX to the ‘Remote PBX Extension’ connected to the FXS device. The routing is
transparent as if the telephone connected to the FXS device is directly connected to the PBX.
The following is required:
■ FXO interfaces with ports connected directly to the PBX lines (shown in the figure below)
■ FXS interfaces for the 'remote PBX extension'
■ Analog phones (POTS)
■ PBX (one or more PBX loop start lines)
■ LAN network
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.
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).
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