B400P/BE400P on DAHDI User Manual
OpenVox Communication Co. LTD.
URL: www.openvox.cn
30
Appendix B
PIN Assignments
Basic Rate ISDN lines can use straight ("flat") modular cable if necessary.
However, twisted-pair are more common.
ISDN U-interface
8-pin RJ45 port PIN
Color
Description
1
8
1
White/Orange
N/A
2
Orange
N/A
3
White/Green
N/A
4
Blue
U interface
5
White/Blue
U interface
6
Green
N/A
7
White/Brown -48VDC Power (optional)
8
Brown
-48VDC Return (optional)
The U-Interface is most commonly used in North American Basic Rate
ISDN systems. The U-Interface is an 8-conductor, modular, RJ-45 jack.
The center two pins (pin 4 and 5) are used for the 2-wire loop. The wiring
of pin 4 and pin 5
are not
polarity sensitive (e.g. 4 and 5 may be crossed).
Optional -48 VDC power may be utilized on RJ-45 pins 7 and 8. This can
be used to power the NT-1 and TE equipments if sufficient power is
