Specifications | 245
Q4EM Quad 4 wire E&M interface
General
Audio 64 kbit/s (PCM A-Law as per ITU G.711)
32, 24 & 16 kbit/s (ADPCM as per ITU G.726 and ANSI
TI.303)
E&M signalling 8 kbit/s per port
Maximum line length 400 metres
Analogue
Transmission performance
characteristics
ITU G.712 E4 for an operating level range of -14 dBr to +4
dBr
Input level range -14.0 dBr to +4.0 dBr in 0.5 dB steps
Output level range -14.0 dBr to +4.0 dBr in 0.5 dB steps
Default output level 0 dBr
Default input level 0 dBr
Maximum level +3.14 dBm0
Port impedance 600
Return loss better than 25 dB over the frequency range 200 - 3600 Hz
Transformer isolation 3.88 kV
End to end gain
Frequency response
0 dB ± 0.1 dB (300-3000 Hz)
0 dB ± 0.5 dB (250-3400 Hz)
Audio line protection Secondary protection
Signal to total distortion > 30 dB (0 dBm0 to -30 dBm0)
> 22 dB (-45 dBm0)
Signalling
E&M Mode independent (external power supply / ground reference
required)
Pulse distortion 4:1 multiplexed < 2.250 ms
Non-multiplexed
≤ 250 µs
M loop current 5.0 to 6.5 mA (constant current)
M detection voltage 9 VDC
M maximum voltage 60 VDC
E circuit impedance 45 closed
> 100 k open
Maximum E circuit current 100 mA
E maximum voltage 60 V
E&M circuit protection E: Current limited to 120 mA, overvoltage to 350 V
M: Current limited to 6.5 mA, overvoltage to 100 V
Diagnostics
Hardware Green LED: M circuit active
Yellow LED: E circuit active
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