OfficeServ 7030 System Description
© SAMSUNG Electronics Co., Ltd.
3-3
3.2 Electrical Specification
3.2.1 Signal Specification
The signal processing protocol means the methods for connecting signals between the trunk
lines, stations and system, and also means the method of providing the status information.
3.2.1.1 Trunk Line Signaling
Loop Start
In processing loop start signals, the on-hook and the 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 Signaling
Characteristics of the ISDN Interface Transmission
The electrical characteristics of the ISDN (BRI) interface comply with the ITU I.430 and
ETS 300 012 standards.
Table 3.5 Electrical Characteristics of the BRI Trunk Line
Category
Specification
Transmission speed
192 kbits/s ±100 ppm
Code
Alternate Mark Inversion (AMI)
Pulse type
Regular square wave: When indicating all valid signals,
comply with the mask (I.403) regardless of the codes.
Transmission media
A pair of twisted lines
Load resistance
120
W
Indicated (pulse) nominal peak voltage 2.75 V
OPEN END
CLOSED END
X
T
E
T
E
GND
-48 VDC
(C.O.)
Key Telephone
