British Telecom ESCORT, System Manual

Page: 7 / 36

1. GENERAL
Escort is a 2 + 6 switching system consisting of a Central
Control Unit (CCU) and up to six key modules each associated with
an approved two wire telephone.
The key module provides direct
key access to each of the systems exchange lines and extensions,
and provides visual indication of the status of each exchange
line. The system is star wired, each key module requiring a
S­
wire connection to the CCU. Two of the extensions may be
provided without key modules, these extensions have limited
access to the systems facilities and may be provided using a two
wire connection to the CCU.
The extension and exchange line
cables are terminated directly on the CCU terminal strips, no
external connection box is required. All extension equipment is
connected to the system via master jacks. Fig.1.1 shows the
general system configuration.
The CCU is a wall mounted, mains powered unit, having a maximum
power consumption of 30VA. The CCU houses a power supply unit
together with two main printed circuit boards each having a 1
+
3
capacity. The system uses custom control and decoder integrated
circuits to provide the control and supervisory functions, and
relay matrix space switching is used making the CCU virtually
transparent to the local exchange.
The system is appr oved for connection to Direct Exchange Lines
and those P B X's given in list "C" of the D T I Sub sidiary
Connection document 84
/
011. The system is not suitable for
connection to PABX's giving a continuous ringing signal .
FIG .1.1 SYSTEM CONFIGURATION
ESCORT
EXCHANGE LINES
ESCORT CCU
MAINS
SUPPLY
>-CABLE EQUIP 2503-
"'
WU-(1 A
-
·-·
-
----
-
KEY MODULE
•••
•••
•••
•
=
Cl
•••
• ••
• ••
•
WU-(IA
=
EXTENSION WITHOUT KEY MODULE
(EXTENSIONS
1
AND /OR
3
ONLY)
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