4RF Aprisa XE User Manual - page 246
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 Ω
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 Ω closed
> 100 kΩ 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