S Bus Configuration - ASCOM Ascotel 2025 System Manual

7.4.2.3

S Bus Configuration

The S bus is a four-wire, serial ISDN bus based on the DSS1 protocol (ETSI stand-
ard). It starts in each case at an S interface of the PBX. Four bus configurations are
possible, depending on the line length and the number of terminals:
Tab. 4.39: S-bus configurations depending on line length and the number of terminals
S bus Short
Length (max.)
PBX « Terminal
150 m
Terminal 1 « Ter-
—
minal 4
Number of termi- 8
nals (max.)
Note:
The maximum number of terminals per S bus depends on the power
requirements of the terminals. (see "Restrictions", Page 4.58).
PBX
haz0028aaena0
Fig. 4.48: S bus, short
Ω
2 x 100
Fig. 4.49: S bus, short, V-shaped
HBT_20321104_04/B0_en
Short, V-shaped
2 x 150 m
—
8
1.
max. 150 m
1. 2. 3.
haz0029aaena0
max. 150 m
ascom
Long
500 m
20 m
4
8 th connection
2. 3.
PBX
Main distribution board
8 th connection point
max. 150 m
Ascotel 2025/2045/2065
Point-to-point
1,000 m
—
1
point
Ω
2 x 100
Ω
2 x 100
Cabling Interfaces 4.65