Aastra 470 System Manual page 145

Installation rules
Always terminate the bus extremity with 2  100  (0.25 W, 5%)!
Note
Circuit type as per EN/IEC 60950: SELV
Cable Requirements
Tab. 63 Requirements for an S bus cable
Cores paires  cores
Stranded
Wire diameter, core
Screening
Ohmic resistance
Characteristic impedance
Wave attenuation
Near / crosstalk attenuation
Terminals
The ETSI protocol must be set in the interface configuration.
Up to 8 terminals of different types can be connected to one S bus.
• Standard ISDN terminals
• ISDN Terminal Adapter
• PC with ISDN card
• Group 4 fax machines
Two call connections are possible simultaneously for each S bus.
1)
Not possible within an AIN
Aastra 470 ab R3.0
syd-0337/1.5 – R3.0 – 05.2013
1  4 or 2  2
yes
0.4...0.6 mm
recommended
< 98 /km (conductor), < 196 /km (loop)
< 125  (100 kHz), < 115  (1 MHz)
< 6 dB/km (100 kHz), < 26 dB/km (1 MHz)
> 54 dB/100 m (1 kHz bis 1 MHz)
1)
, etc.
Installation
145