AT&T Bell System Plant Series Test Instructions

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BELL SYSTEM PRACTICES
Plant Series
SECTION 310-282-501
Issue 1, December, 1965
AT& TCo Standard
21 A TESTBOARD
OPERATIONAL TESTS
CONTENTS
1. GENERAL .
2. OPERATIONAL TESTS ON NETWORK
TRUNKS.
3. OPERATIONAL TESTS ON SUBSCRIBER
LINES
4. OPERATIONAL TESTS ON CON-
CENTRATOR TRUNKS
5. OPERATIONAL TESTS ON 101 TEST
TRUNKS AND SERVICE CIRCUITS .
A. Busy Test
B. Keypulsing (216) on a CON Cord.
C. Dial Pulsing on a CON Cord .
D. Dial Pulsing on an SS1 Order
Wire
E. Incoming Calls on 101 Test
Trunks. .
6. OPERATIONAL TESTS ON MUL II-
ADDRESS/BROADCAST BRIDGES.
A. Transmission Measurements
B. Sensitivity and Response
Measurements .
7.
SIGNALING AND ALARM FUNCTIONS .
A. Signaling Tests on E and M Leads .
B. Retirement of a Permanent Signal .
C. Single-Frequency Tone Tests .
D. Teletypewriter Circuit Controls
and Alarms.
8. TESTING FACILITIES .
A. Transmission Measuring Circuit,
SD-95900-01.
B. Auxiliary Test Equipment
C. Coded Test Lines
9. REFERENCES
1. GENERAL
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1.01
This section describes procedures for mak-
ing operational tests from a 21A testboard
as used in a 4-wire, No. 1 electronic switching
system (ESS) provided for switched services net-
works (SSN).
1.02
Automatic routine testing of network
trunks connecting to the ESS is accomp.
lished by the automatic transmission measuring
system (ATMS). A test failure is alarmed at the
21A testboard and an information printout is
made at a teletypewriter bay. Manual testing is
initiated from the testboard.
1.03
The testboard and an auxiliary testing bay
contain equipment for making transmis-
sion loss measurements, impulse and message-
type noise measurements, voiceband gain and de-
lay tests, and signaling and supervisory tests. By
means of test trunks, the testboard may be asso-
ciated with 904-type data test bays or a lOC tele-
graph testboard for data or telegraph operational
checks, as required.
1.04
All operational tests on network trunks
and subscriber lines are performed through
the switching system. Access to the communica-
tion paths of trunks and lines connecting to the
ESS is obtained via access circuits provided in the
testboard. Direct access to E and M signaling
leads of network trunks and lines is provided at
testboard jacks associated with the particular
trunk or line.
1.05
Progress and error information in conduct-
ing operational tests through the ESS is
provided by the P & E lamp. The P & E lamp,
when lighted momentarily following a signaled re-
quest from the testboard, indicates that the re-
quest has been acted upon by the ESS central con-
trol. If incorrect digits are pulsed while keying
address information, the P & E lamp is flashed at
120 ipm. When central control is unable to com-
plete a requested function, the P & E lamp is
flashed at 60 ipm. If the inability to perform the
requested function is temporary, the P
&
E lamp
is extinguished after a few seconds.
1.06
An access circuit off-normal (OFF NOR)
warning lamp is lighted when a test cord is
connected to the access circuit jack or when any
@ American Telephone and Telegraph Company, 1965
Printed in U.S.A.
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