Electrical Specifications For Bri Isdn; Backup Modules For The Procurve Secure Router - HP 7102dl - ProCurve Secure Router Configuration Manual

ISDN Interfaces. The ISDN standard defines four interfaces, or points, at
which equipment can be added to the ISDN network:
U interface (between the NT1 and the NIU)
T interface (between the NT2 and the NT1)
S interface (between the TE1 and the NT2)
R interface (between the TE2 and the TA)
In Europe, Asia, and all other locations outside of North America, PTTs supply
the NT devices. The demarc then falls between the TE (in your case, the
router) and the NT1 at the S/T interface. The ProCurve Secure Router provides
an ISDN BRI S/T module, which enables a backup interface to connect to
either the NT2 or the NT1 provided by your PTT.
In North America, the subscriber must provide the NT devices. The demarc
falls between the NT devices and the public carrier's NIU (or smart jack) at
the U interface. The ProCurve Secure Router's ISDN BRI U module contains
the NT1 and enables a backup interface to function as a U interface.

Electrical Specifications for BRI ISDN

ISDN lines use 2B1Q coding, which uses four signal levels rather than the two
of T1- or E1-carrier lines. Each of the four levels, represented by a quaternary,
corresponds to a combination of two bits. For example, the signal level for 1
followed by 1 is different for that of 1 followed by 0. This coding scheme allows
BRI ISDN lines to compress data. Also, 2B1Q operates at a lower frequency
range than T1/E1 encoding and sustains fewer losses with fewer repeaters.

Backup Modules for the ProCurve Secure Router

All narrow Data Link modules on the ProCurve Secure Router provide an extra
port for a backup interface. To activate the backup interface, you must
purchase and install one of the following backup modules:
analog
ISDN BRI U
ISDN BRI S/T
The ProCurve Secure Router supports BRI ISDN, which provides a transmis-
sion rate of 64 Kbps or 128 Kbps. The analog module on the ProCurve Secure
Router supports between 300 bps and 33.6 Kbps.
Configuring Backup WAN Connections
Backing Up Primary WAN Connections
3-9