Telos Zephyr Xstream - Manual (Page 37)

USER’S MANUAL
Section 3: GUIDED TOUR of the HARDWARE 25
ISDN Interface
w
IMPORTANT!
As with any piece of modern electronic gear, it is advisable that precautions be taken to
prevent damage caused by power surges. Standard telephone line surge protectors can be used
to offer some degree of protection at the U interface jack. Special protectors are available for
the S interface.
It is the user’s responsibility to ensure that adequate protection is provided.
Section 5 has additional information.
U Interface (2 wire) ‐ for use in the USA and Canada
The ISDN U interface is for connection with “raw” 2B1Q BRI ISDN circuits as provided primarily in
the USA & Canada. When this jack is used, you will be using Zephyr Xstream’s built‐in NT1
(Network Terminator). This is a 6‐position/4‐pin miniature modular jack with the following pin
out.
PIN FUNCTION
1 No Connection
2 No Connection
3 Line (R)
4 Line (T)
5 No Connection
6 No Connection (Top)
ISDN U interface connector. Note, the polarity
of the line connections should not matter.
U Interface Sync LED
A green LED, located below the U interface jack, shows the status of the built‐in NT1. Normal
status is indicated by the LED being lit. Rapid flashing (about five times per second) indicates a
loss of the ISDN at the lowest (physical) level. If the NT1 can contact the central office (or an
active U repeater), the LED will blink slowly (about once per second) as the S connection
between the NT1 and the rest of the ISDN interface occurs. The LED will come on solidly when
all handshaking is completed and the basic line connection (OSI Layer 1) is good. If this LED does
not light continuously once you have connected your ISDN circuit, you may wish to skip ahead to
Section 13.4 (Deep Tech Information ‐ Troubleshooting) for information on troubleshooting
problems.
U
U Sync LED