Telos Zephyr User Manual page 91

HOW TO ORDER ISDN
Dealing with The Phone Company
As is often the case when we broadcasters interface with the phone people, the lines of
communication on ISDN can get a little tangled. Face it: we are not the usual customer.
The first order of business is to find someone who knows what ISDN is. While your
usual account agent will be the normal entry point, you may be talking to a number of
phone people before you find one who understands your needs. Some of the regional
Bell companies offer a single point of contact number for switched digital services.
Some Telcos use "Resellers" or "Agents". If so, you should be sure to ask what
experience the particular agent has with ordering lines for high fidelity audio codecs. If
in doubt, go direct to the Telco. And always order your line in writing using the ISDN
order forms in the Appendix of this manual.
This section is intended to be used as a reference. It is probably not necessary to
understand everything in order to get an ISDN line for a Zephyr.
The easiest way to order the line is to use the Faxable form in the Appendix, ISDN BRI,
Zephyr, & You. There is also a list of contact telephone numbers for most of the regional
telephone companies.
Details, Details
In order to communicate accurately what it is you need, you might want to learn about
the nature of the ISDN service and the vocabulary used to describe it. As with anything,
for best results, it helps to know what you are talking about. We already have a good
start, but there is more to learn.
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.
CSV is for calls to standard voice phone service and allows ISDN to interwork with
analog phone lines and phones. CSD is required for Zephyr connections. Even though
you may be sending voice, the codec bitstream output looks like computer data to the
phone network. Alternate CSD/CSV means both are supported.
HOT TIP!
While the D channel is always present for signaling purposes,
it can, in theory, be used for packet data connections. ISDN
lines where the D channel is used for signaling only are
sometimes referred to as 2B+0D rather than 2B+D service. D
channel packet service is not widely available.
Section 5 ISDN
91