CHAPTER 3. OfficeServ 7400 Specifications
3-4
© Samsung Business Communications
3.2 Electrical Specifications
3.2.1 Signal Specifications
The signal processing protocol refers to the method of sending signals between the trunk
lines, stations and system, and how status information is provided.
3.2.1.1 Trunk Line Signalling Type
Loop Start
In processing loop start signals, the on-hook and off-hook statuses are controlled by the flow of
electric current. The loop is a closed loop trunk circuit or a standard 2500-type set loop.
Figure 3.1 Trunk Line Loop Start Signalling
T1 Trunk Line
y
The electrical characteristics of the T1 trunk line comply with the ITU G.703 and G.704
standards.
Table 3.5 Electrical Characteristics of the T1 Trunk Line
Categories
Specifications
Transmission 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) regard-
less of the codes.
Transmission media
A pair of twisted lines
Load resistance
100
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
OPEN END
CLOSED END
X
T
E
T
E
GND
-48 VDC
(C.O.)
Key Telephone
