Telos Zephyr, User Manual

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Section 15 APPENDICES 251
CSV is for interworking with standard voice phone service and allows ISDN to call to
analog phone lines and phones. The Zephyr allows outgoing voice calls on either of the
channels if you have CSV. The Zephyr’s voice capability exists on both channels, even
when your Zephyr is a mono version. Thus you can make calls to any normal telephone
number on one channel while a program is being transmitted on the other. This is a
feature you may want to use.
You will be ordering an ISDN BRI 2B+D line with CSD and CSV (sometimes called
alternate CSD/CSV) available on any B channel.
IIf you do not require the Zephyr’s ability to call a regular (POTS) telephone you may
omit the CSV option.
56/64kbps
All ISDN BRIs have a 64 kbps per channel capacity and almost all local calls operate at
this rate. Some long distance connections, however, operate at only 56 kbps.
The Zephyr provides standard rate adaptation (officially known as CCITT V.110) from 56
to 64 kbps when required. Bit rate adaptation happens automatically within the Zephyr
depending upon the rate of an incoming call.
In our experience, the only sure way to know the capacity of a given connection is to try
it, first at 64 kbps and then at 56 kbps if the higher rate fails.
If you find that you have the 56 kbps limit on your line, you might want to request the
Telco to upgrade the “RBOC- to- IXC” circuit.
NT1s
The ISDN standard specifies two reference points, the “U” and the “S” 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 and Asia the NT1 is always provided by the phone company, and only the “4
wire” S interface may be on user equipment. Zephyrs shipped outside of the USA and
Canada have the “S” interface only, as do units sold prior to 1996. In the USA and
Canada the NT1 is provided by the user and is therefore built- in to the ISDN terminal
adapter.
Terminals and Terminal Types
Any equipment connected to an ISDN line is a ‘terminal’ – whether phone, computer,
or Zephyr. 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 varies depending upon protocol and is included
on the order forms.