OfficeServ 7200 System Description
© SAMSUNG Electronics Co., Ltd.
3-7
3.2 Electrical Specifications
3.2.1 Signal Specifications
The signal processing protocol is used for interfacing messages between the trunk
lines/stations and system. Also, the signal processing protocol refers to the method for
providing status information.
3.2.1.1 Signaling Type of the Trunk Line
Loop Start
When processing the loop start signals, the on-hook and off-hook status is controlled 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 Signaling
T1 Trunk Line
The electrical characteristics of the T1 trunk line comply with the ITU G.703 and G.704
standards.
Table 3.9 Electrical Characteristics of the T1 Trunk Line
Category
Specification
Transfer speed
1544 Kbits/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
A pair of twisted lines
Load resistance
100
Indicated (pulse) nominal peak voltage
3.00 V
Signal
Level
Power at the frequency of
772 kHz
±12~19 dBm
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
