Bell 502-503-120 Service Manual

BELLSYSTEMPRACTICES SECTION502-503-120
AT&TCo Standard Issue8, July 1982

REFERENCE

2503-TYPE TELEPHONE SETS

IDENTIFICATION AND CONNECTIONS

1. GENERAL control with the exclusion key operated, refer to

1.01 This section contains information for the
2503C manufacture discontinued (MD) and 2.03 The 2503C (MD): With the exclusion key

2503CM (modular) (Fig. 1) telephone sets. Refer to operated (up position) this telephone set may
Section 502-500-110 for common maintenance infor- be used with the J1D402B data set to provide data

mation for 0- and 1-button telephone sets. service. With the exclusion key nonoperated (normal

1.02 The reasons for reissuing this section are
listed below. Revision arrows are used to era- Note: The relationship of features to exclu-

phasize the more significant changes.

• Add the 641E jack 2.04 These telephone sets are used in Data Access

. Add the D-180896 Kit of Parts (polarity owned equipment is connected to the DDD network

guard) through a coupler. Figure 2 and 3 provide connection

• Show the 819040528 (P-90D052)guard assem- phone sets. The 2503CM is a modular set which is
bly MD. shipped with a G15A handset but without the H4DU

2. IDENTIFICATION handset cord or the D8AA mounting cord, which

2.01 The 2503-type telephone sets are desk sets in- 2.05 For application of these telephone sets, refer

tended for use in conjunction with other to Division 590.

equipment to provide DATAPHONE ® data commu-
nications service. 2.06 Table B lists replaceable components for these

2.02 The 2503CM: With the exclusion key
nonoperated (normal position) this telephone 2.07 When a polarity guard is required with these

set may be used with the J1D402B data set to provide sets, install the D-180896 Kit of Parts (guard
data service with monitoring of computer-generated assembly) or the 819040528 guard assembly (MD) as
voice replies. With the exclusion key operated (up shown in Table C. Polarity guards should be installed

position) the set provides regular telephone service, only when authorized by local instructions to prevent
To deactivate monitoring feature, refer to Fig. 3, battery and ground reversals encountered in end-to-
Note 4. To use the telephone set to provide data set end signaling installations.

Table A.

position) the set provides regular telephone service.

sion key differs in the 2503C (MD) and 2503CM
telephone sets.

Arrangements (DAA) where the customer-

information on the 2503C (MD) and 2503CM tele-

must be ordered separately.

sets.

NOTICE

Not for use or disclosure outside the

Bell System except under written agreement

Printed in U.S.A. Page 1

SECTION 502-503-120

EXCLUSION KEY

FACEPLATE

LATCH

Fig. 1m2503CM Telephone Set

$TABLE A_I

TO PROVIDE DATA SET CONTROL WITH

EXCLUSION KEY OPERATED (2503CM ONLY)

LEAD COLOR

Exclusion

Key

641E or

641D (MD) O-W 8 7

Jack

S E2 L2
R L2 E2

BR 1 R

O R 1

REMOVEFROM CONNECTTO

TERM.STRIP NET. TERM.STRIP NET.

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