Telos Zephyr Xstream User Manual page 148

You must have this number, and it must be 100% correct, or the system won't work. Don't let
the installer depart without leaving them. You've been warned!
h
HOT TIP!
Most phone companies in the USA have settled on a standardized SPID format, based on the
telephone number. This format is area code+7 digit phone number + 0101. For example, if
your phone number was (321) 555-1234 then your SPID would be 32155512340101.
For a list of known working SPID formats, listed by telephone company, see Appendix 4
(Known Working SPIDs by Telephone Company).
i
ISDN TIP!
In an emergency, to save a remote, you might be able to get a line to work without the proper
SPIDs by dialing into it. If it works, this fix is only temporary, and the line will fail to
initialize next time the Zephyr Xstream is booted.
i
ISDN TIP!
If you see SPID ERROR as your line status, your SPID for that channel is incorrect. In this
case check the SPID. For a list of known working SPID formats listed by telephone company
see Appendix 4 (Known Working SPIDs by Telephone Company).
Directory Numbers (DNs) and Multiple Subscriber Numbers (MSNs)
Directory Numbers
Directory Numbers, or DNs for short, are the 7 digit telephone numbers assigned to the ISDN
lines (as would typically found in the telephone directory) in the USA & Canada. You may be
assigned one or two, depending upon the line configuration. In the case where you have two
active ISDN B channels, you will usually have two DNs (but not always). However, the "physical"
channels (i.e. "time slots") are independent from the "logical" numbers. A call coming in on the
second number will be assigned the first physical B channel, if it is not already occupied.
Therefore, there must be some way for the Zephyr Xstream to sort out which call goes to which
channel/line. The DN is used for this function when the USA ISDN protocols are used.
When a call rings in, it contains set‐up information, which includes the DN that was dialed by the
originating caller. The last 4 digits are matched with the DNs programmed into the Zephyr
Xstream, and the proper assignment is made. Therefore, problems with Directory Numbers will
virtually always be difficulties related to receiving calls.
USER'S MANUAL
Section 7: ISDN BASICS 136