Telos Zephyr, Руководство пользователя

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Section 5 ISDN
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Zephyr allows the option of a voice call on either of the channels as well as the coded
hi- fi audio. The Zephyr’s voice capability exists on both channels, even when your
Zephyr is a 3- DSP “mono” version. Thus you can make calls to any normal telephone
number on one channel while a program is being transmitted on the other. A limit of
one voice call may be made.
Therefore, you may want to order CSV as well as CSD on one or both B channels. To get
a line with one B channel to be used with either hi- fi or speech, you would request an
ISDN BRI 1B+D line with alternate CSV/CSD capability; for both B channels, you would
order an ISDN BRI 2B+D line with alternate CSV/CSD on both channels; if you don’t
need voice possibility on the channels, you want 2B+D with only CSD enabled.
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’ (NT1) converts this to the two- pair S interface.
In Europe and Asia the NT1 is always provided by the phone company, and only the S
interface may be on user equipment. Zephyr’s shipped outside the USA and Canada
have the S interface only, as do units made prior to 1996. In the USA and Canada the
NT1 is usually provided by the user, however Zephyrs sold in the US and Canada and
therefore built- in to the ISDN terminal adapter.
In the USA and Canada, an external NT1 can be powered by the Zephyr.
Refer to manual section 3 (Zephyr at a Glance), and section 4 (Installation & Basic
Operation) for additional information on NT1s.
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 given below.
DEEP TECH NOTE!
Both in contrast to PSD, Packet Switched Data, which is
possible, but irrelevant to our needs.