Siemens I-SURF - Manual (Page 69)

Appendix
63
A3: ISDN S
0
Interface Pin Assignment
ISDN S
0
interface pin assignment (RJ45 plug/jack)
(CCITT I.430/ISO 8877)
Pin Signal
1 Not used
2 Not used
3 STA (Sending A)
4 SRA (Receiving A)
5 SRB (Receiving B)
6 STB (Sending B)
7 Not used
8 Not used
A4: Terminal Resistor for ISDN S
0
Interface
The last jack on your ISDN S
0
bus must be terminated with two 100 ohm terminal
resistors.