Specifications

OfficeServ 7200 General Description Guide CHAPTER 3. OfficeServ 7200 Specifications
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2.1.1 Signalling Type of the Trunk Line
Loop Start
When processing the loop start signals, the on-hook and off-hook status is con-
trolled by the flow of the electric current. The loop is a closed loop trunk circuit or
standard 2500-type set loop.
Figure 3.1 Trunk Line Loop Start Signalling
T1 Trunk Line
The electrical characteristics of the T1 trunk line should comply with the ITU G.703
and G.704 standards.
Table 3.4 Electrical Characteristics of the T1 Trunk Line
Category Specification
Transfer speed 1544 kbit/s ±50 ppm
Code AMI or B8ZS
Pulse type Regular square wave : When indicating all valid signals,
comply with the mask (G.703) regardless of the codes.
Transmission media Pair of twisted lines
Load resistance 120 Ω
Indicated (pulse) nominal peak voltage 3.00 V
Power at the frequency of
772 kHz
±12 ~ ±19 dBm Signal
Level
Power at the frequency of
1544 kHz
25 dB or higher when the power is less than the power
at the frequency of 772 kHz
The signalling specifications and signalling method of the T1 trunk line should
comply with the ITU G.703 and G.704 standards.
OPEN END CLOSED END
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