363-206-305
Technical Specifications
10-72  
Issue 3 June 2000
Table 10-32. Transmission Specifications — VF Channel Units with Adjustable 
Settings  
Parameter 
2-Wire E 
SPOTS
®
 
CUs(AUA42, AUA43) 
4-Wire CUs
(AUA41, AUA44, AUA54) 
Loop Resistance (beyond 
HDT, excluding telset) 
CSA loops  0-2800 ohms (loop start, 
ground-start) 0-5000 ohms 
(DX)
Gain Range (Granularity) 
Metallic Interface to digital 
line
−
1.0 dB to 6.75 dB
(in 0.25-dB steps) 
Range depends on function 
code
Digital line to metallic 
interface 
−
8.0 dB to 1.5 dB 
(in 0.25-dB steps)
Granularity 
=
 0.1 dB 
Gain Tracking 
Input 
−
37 to 
+
3 dBm 
±
 0.25 dB 
±
 0.25 dB 
Input 
−
50 to 
−
37 dBm 
±
 0.50 dB 
±
 0.50 dB 
Equalization  (Slope type) Equalized CSA 
cable roll-off at 0.4 kHz 
varies from 0.0 dB to 1.1 
dB; at 2.8 kHz, roll-off 
varies from 0.3 dB to 1.75 
dB 
Post-equalization of cable 
less than 15 dB (H88) or 18 
kft (NL) is comparable to D4 
4FXS CU (J98726SB). Pre-
equalization and post-
equalization available by 
emulating 150-ohm 
mismatch. 
Structural Impedance 
 600 ohms 
+
 2.16 
µ
F or 900 
ohms 
+
 2.16 
µ
F
 600 ohms or 1200 ohms
ERL/SRL (2-wire return loss 
with 4-wire path broken)
28/20 dB 
RL (any Hz) / RL (1 kHz)    23/28 dB 
Balance Capability, CSA 
loops
ERL better than 12 dB at 
digital line interface of 
channel unit facing loop 
— 
Longitudinal Balance 
(IEEE method)
 
AUA42 AUA43 
200 Hz  63 dB  58 dB  67 dB 
500 Hz  63 dB  58 dB  67 dB 
1,000 Hz  63 dB  58 dB  67 dB 
 
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