4.2 CONNECTING TO THE VOICE PORTS
Both voice ports utilize a Data Access Arrangement (DAA) to
interface with telephone equipment. Both ports also utilize an ADPCM
CODEC to convert voice to digital information. The voice ports (V1 and
V2) use integral RJ-11 connectors. The FXS and FXO ports look the
same on the back of the VDQM
QuikConnect™ Module. Each is
shown on the rear of the VDQM module (See Figure 4, below).
Voice Port 1:
Port 1 is permanently defined as a 32Kbs channel
conforming to G.721, capable of supporting normal
speech and Fax transmissions up to 14.4Kbs.
Voice Port 2:
Port 2 is permanently defined as a 24Kbs channel
conforming to G.723, intended for voice transmission
only.
4.2.1 Identifying FXS/FXO Voice Modules
The VDQM is factory defined as a FXO (Foreign Exchange Service)
or FXO (Foreign Exchange Office) on both voice ports at the factory. To
determine the factory configuration of your VDQM, look at the label on
the inside of the rear panel. You will see one of the following Model
number codes, plus a serial number.
Model IM1/JS
-
FXS Voice Ports
Model IM1/JO
-
FXO Voice Ports
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Figure 4. VDM Rear Panel
Voice Port 1
Voice Port 2
4.2.2 Connecting to an FXS Voice Port (Model IM1/JS)
The FXS (looks like central office) ports are designed as a loop
start telephone interfaces. Each is designed to connect to a telephone
or fax machine using a two-wire interface (as shown below).
VDQM
Telephone/Fax
RJ-11 Pin No.
RJ-11 Pin No.
3 (TIP)
3 (TIP)
4 (RING)
4 (RING)
4.2.3 Connecting to an FXO Voice Port (Model IM1/JO)
The FXO (looks like telephone) ports are designed as loop start
telephone interfaces. Each is designed to connect to a PBX using a
two-wire interface (as shown below).
VDQM
PBX
RJ-11 Pin No.
RJ-11 Pin No.
3 (TX+)
3 (TX+)
4 (TX-)
4 (TX-)
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Warning! Connecting the FXS port of the VDM
to a telephone line WILL damage the VDM and
possibly the telephone line. ONLY connect
telephones or fax machines (or similar
equipment) to the FXS port.
NOTE! The FXO ports are designed to be
connected to a PBX (or similar equipment). If
you wish to connect the FXS ports directly to
PSTN, you MUST obtain approval from the PTT.
