Telos Zephyr Xstream - Manual (Page 346)

USER’S MANUAL
Appendix 8 – Ordering ISDN for the USA and Canada 334
providing you with the phone numbers of your B channels (often called "Directory Numbers", or
"DNs") and your SPIDs!
Directory Number (DN)
These are simply your seven digit phone numbers, as would be listed in your local telephone
directory, and need to be entered into your Zephyr Xstream. Normally each ISDN BRI circuit will
have two DNs and two SPIDs. Each DN corresponds to a given SPID and when you enter this
information, you must enter them to reflect this relationship.
CSD and CSV
Recall that each ISDN BRI has two possible B channels. It is possible to order a line with one or
both of the B channels enabled – and each may be enabled for voice and/or data use. Phone
terminology for the class of service is CSV for Circuit Switched Voice and CSD for Circuit
Switched Data. (In contrast to PSD, Packet Switched Data, which is possible but irrelevant to our
needs.)
CSV is not required for Telos Zephyr Xstream hi‐fidelity audio connections. Even though you
may be sending voice, the codec’s output will be in a data form and must be handled
transparently by the telephone network. This happens because the Zephyr Xstream indicates
that this is a CSD call (over the D channel) when the call is set up.
CSV is for interworking with voice phone service and allows ISDN to interwork with analog
phone lines and phones. CSV is required to place calls to a Zephyr Xport that is using a POTS
line.
You will be ordering one or more ISDN BRI 2B+D circuits with CSD (required) and CSV (optional)
on each B channel. Alternate CSD/CSV should be requested.
NT1s
The ISDN standard specifies two reference points, the “U” (2‐wire) and the “S” (4‐wire)
interfaces. The U is the single‐pair bare copper from the Telco CO. A device called a “Network
Termination, Type 1” converts this to the two‐pair S interface.
In Europe, Asia, South America, and most of the world, the NT1 is always provided by the phone
company. The Zephyr Xstream provides both the U interface (on an 6‐position 4‐pin miniature
“RJ‐11 style” modular connector) and the S interface (on an 8‐position 8‐pin miniature “RJ‐45
style” modular connector).
Terminals and Terminal Types
Any equipment connected to an ISDN line is a ‘terminal’ – whether phone, computer, or codec.
“Point‐to‐point” lines support one terminal, while “multipoint” lines can have up to eight in
some applications.
“Terminal Type” is a parameter sometimes requested by the phone people. The appropriate
value for the Zephyr Xstream varies depending upon protocol and is included on the order
forms.