APPENDIX A: FXS Voice/Fax Interface Module
61
back panel, then secure it on the left side with a
Phillips-head screw.
A.2 Strapping
Do not alter any of the movable straps on the FXS
Interface Module. They are set at the factory to
match the type of memory installed, and changing
the configuration could easily cause the Card to
stop working altogether.
A.3 Removing or Replacing the Module
See
Section 3.4
for removal/replacement of the
Multiserver 500 interface modules, including the
FXS interface card.
A.4 Specifications
Signals Supported —
Analog voice and Group 3
facsimile (fax)
Fax Signal Types: —
V.21 channel 2, V.27 ter 2400,
V.27 ter 4800, V.29 7200, and V.29 9600
Port Impedance —
Enhanced Model (software-selectable):
600
Ω
(Default): Matches line impedance of 600
Ω
in series with a 2.15-µf capacitor
Complex: Matches line impedance of 370
Ω
in
series with a parallel network of a 0.31-µf
capacitor and a 620-
Ω
resistor
or
220
Ω
in series with a parallel network of a 0.12-
µf capacitor and an 820-
Ω
resistor
Standard Model:
Fixed at 600
Ω
in series with a 2.15-µf capacitor
Insertion Loss —
2 dB nominal @ 1000 Hz (End-
to-End) between Transmit and Receive of Port 1
and Transmit and Receive of Port 2. Example:
Port 1 is FXS LS port and Port 2 is FXO LS port.
Port Return Loss —
Echo:
≥
22 dB; Singing:
≥
18
dB; 200 to 3400 Hz:
≥
16 dB
Longitudinal Balance —
200 to 1000 Hz:
≥
58 dB;
1000 to 3400 Hz:
≥
48 dB
Input and Output Level Adjustments —
If you
operate your equipment in the U.S.A. or
Canada, input gain and output attenuation are
set at the factory to 0/0 dBm, and must not be
changed. In other countries, follow the
standards of the country where the equipment is
used.
Maximum Input and Output Levels —
0 dBm
Frequency Response Over the Range of 300 Hz to
3400 Hz —
+1 dB/-2 dB with respect to 1000 Hz
Idle Channel Noise —
Inband, “C” Message:
≥
20
dBrnc; Psofometric:
≥
60 dBmpo; Out of band,
10 KHz to 10 MHz Transverse or Longitudinal
Noise:
≤
-70 dBm (enhanced models only)
Non-Linear Distortion (Multitone Signal) —
Second Harmonic:
≥
40 dB below signal; Third
Harmonic:
≥
40 dB below signal
Signal-to-Noise Ratio —
≥
37 dB @ 1000 Hz
Echo Suppression —
≥
35 dB
Echo Canceling —
≤
16 ms (
≤
1000 km or
600 miles)
Crosstalk (near/far end) Between Channels —
≤
75 dB
Signaling —
Battery current into 130-W load:
≥
36
milliamperes; Battery current into 900-W total
loop: 20 milliamperes minimum
DC Loop Range —
≤
900
Ω
DTMF Distortion (AC) —
≤
1.5 %
DP Distortion —
≤
2 %
Ringing Tone (Software Selectable) —
20 Hz, 25
Hz (default), or 50 Hz
Ringing Voltage (AC load of 2 ringers [4000 W]
and zero line) —
25-Hz Tone:
≥
54 Vrms ; 20- and
50-Hz Tones:
≥
50 Vrms
Ringing Current —
≤
15 milliamperes into 5000-
Ω
load
Ring Cadence —
Repeated ring (matches ringing
cadence from remote voice/fax channel),
interrupted ring 2/4 (2 seconds on, 4 seconds
off), or interrupted ring 2/5 (ring two times for
0.4 separated by 0.2 second, then off for two
seconds)
