9
1 Introduction to the AVM ISDN-Controller T1/T1-B
The ISDN network ends at the subscriber’s premises in
the network terminator (NT). This device provides the
subscriber with the S
2M
interface. The abbreviation S
2M
refers to the total throughput at this interface, which is
about 2 Mbit/s. The network operator may carry the
signal over certain four-conductor paired copper cables
(120W impedance), over coaxial cable (75W imped-
ance), or over fiber optic lines. Depending on the
medium used, the NT’s network-side interface to the
local switching station is designated as the U
K2
(copper)
or U
G2
(fiber optic) interface. Accordingly, the NT
installed by Deutsche Telekom AG is either an NTPMKU
(U
K2
), an NTPMGF (U
G2
) or an NTMP.
The AVM ISDN-Controller T1/T1-B is connected to
the NT’s S
2M
interface by a four-lead shielded twisted
pair cable. The NT must be supplied with electrical
power, either through a separate power supply or
through an adapter. The power supply or adapter must
be installed by the network operator.
1.2 The AVM ISDN-Controller T1/T1-B
The AVM ISDN-Controller T1/T1-B is a complete
ISDN system solution for the primary rate (S
2M
) inter-
face. It supports all 30 B channels of the S
2M
line
simultaneously. Its high capacity makes the AVM ISDN-
Controller T1/T1-B especially suited to server appli-
cations.
The Controller is constructed as a 19" unit and can be
installed either free-standing or in a 19" equipment
rack.
The hardware architecture of the T1, based on a
network of CPUs, is a superior engineering solution
with a high degree of flexibility and scalability. The
difference in the AVM ISDN-Controller T1-B as
compared with the AVM ISDN-Controller T1 consists
in the incorporation of additional hardware for in-
creased performance capabilities: the AVM ISDN-