Telos NX12 - Manual (Page 127)

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with an audio codec such as the Zephyr or Zephyr Xstream, then CSD should be ordered as it
is required for audio codec calls.
CSV is for interworking with voice phone service and allows ISDN to interwork with analog
phone lines and phones.
You will be ordering one or more ISDN BRI 2B+D circuits with CSV (required) and CSD
(optional) on each B channel.
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, Asia, South America, and most of the world the NT1 is always provided by the
phone company. Therefore, Telos TWOx12s shipped outside the USA & Canada have the S
interface. In the USA & Canada the NT1 must be provided by the user, and is therefore built-in
to the TWOx12’s ISDN terminal adapter. In this case, the “U” (RJ-11) interface is provided.
Terminals and Terminal Types
Any equipment connected to an ISDN line is a ‘terminal’ – whether phone, computer, or
Hybrid. 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 Nx12 varies depending upon protocol and is included on the order forms.
IOC Capability Packages (provisioning package)
More and more Telcos are using ISDN Ordering Code (IOC) capability packages for ISDN
ordering (National ISDN protocol only). If your telephone company uses these you need only
tell them you need IOC package ‘S’ and an RJ-11 style (SJA48) jack. We still recommend that
you fax them these forms as well.
Hunt Groups
Just as with analog lines, ISDN BRI lines can be placed in a ‘hunt group’ where a single number
can be given to callers and the calls will ‘roll over’ from busy channels to idle channels. This is
sometimes called ISG (incoming service grouping) or rollover lines. This would usually be a
requirement for an on-air phone system. You may choose to exclude 1 or 2 channels from the
hunt group (i.e. the Hot line and the Warm line). Be sure to specify to your Telco how you
expect this to work.
FAXABLE ISDN ORDER FORM (for the USA & Canada)
The following form can be used to place orders for ISDN lines in the USA & Canada. Com-
plete the top portion of the form and send all three pages to the phone company. We suggest
that you keep the form handy and show it to the installer when he or she puts in your line and
ask the installer to verify with the switch programmer (at the central office) that your line is
configured as ordered.
You only need to send the first page if the Telco uses IOC
(ISDN Order Code Capability)
packages for ISDN specification.