ZXDSL 9210 (V3.1) Broadband Universal Access Equipment Technical Manual
3-6
The line interface of the ADSL device must be able to be free from any fire risk
within 15 minutes when it contacts directly one or two 220 V (50 Hz)
conductors.
3.1.4.2 Technical Indices of Splitter Interface
1. POTS-ADSL
splitter
1) DC
resistance
DC resistance at the PSTN interface of ADSL in case of short circuit at point
U-C:
≤
25
Ω
. DC resistance of PSTN interface in case of open circuit at point
U-C:
≥
5 M
Ω
.
2) AC impedance characteristic
The nominal impedance of the splitter at the audio interface should be triplet
impedance. If the interface is designed according to Z interface specifications,
that impedance should be 600
Ω
. Both are balanced interfaces. The impedance
characteristic is represented by RL. The RL at the audio interface point meets
the requirements shown in Fig. 3.1-2.
R
etu
rn
lo
ss
dB
14
18
500
2000
300
3400Hz
Frequency
Fig. 3.1-2 RL Indices of Z Interface
3) Longitudinal conversion loss
The longitudinal conversion loss generated by unbalanced earth impedance of
the CO or remote splitter at the audio interface point should be greater than 58
dB on the frequency band of 0.2 to 1 kHz, and greater than 53 dB on 3 kHz.