Bell System 500B Series Test Procedures/Instructions

BEU SYSTEM PRACTICES
AT & TCo Standard
PRELIMINARY COPY
5008 DSU 4-7
SECTION 595-200-501
lss_ue 1, July 1981
DIGIT AL DAT A SYSTEM
500B-TYPE DAT A SERVICE UNIT
TEST PROCEDURES
CONTENTS PAGE
1. GENERAL
1
2. APPARATUS
2
3.
TEST
PROCEDURES-912A WDTS AND
914C
DTS
2
A. local Test
5
B.
DSU Functional Test 6
C.
Straightaway Test 8
4. TEST PROCEDURES-921A DTS
10
A. local Test
12
B. DSU Functional Test
14
C.
Straightaway Test
17
1. GENERAL
1.01
This section contains procedures to be used
when testing the 500B-type data service unit
(DSU). Procedures for investigating a trouble condi-
tion are given in Section 5~5-200-301, entitled 500B-
Tvt>e Data Service Unit--Maintenance--Digital
Data System.
1.02
Whenever this section is reissued the rea-
son(s) for reissue will be given in this para-
graph.
1.03
The tests covered in this section are listed and
defined below.
(a) Local Test: This is a partial test of the cus-
tomer interface leads, the DSU transmit and
receive logic, and the power supply. In order to
perform this test, the DSU must be connected to
ac power.
(b) DSU Functional Test: This test verifies
the operation of circuits within the DSU
which control the zero suppression code and idle
code generation and detection. The ability of the
DSU to transmit and receive data and contr-ol
codes in conjunction with the associated
channel service unit
(CSU)
and office
channel unit (OCU) is determined by this test. In
addition, the DSU is monitored for response to
control codes, generated by the serving test center
(STC), which determine loopback modes (DSU and
CHAN). Voice coordination with the STC is re-
quired to perform this test. This voice coordina-
tion is not over the digital data system (DDS), but
must be via the public switched network (PSN).
(c) Straightaway Test: The purpose of this
test is to evaluate the performance of the DDS
channel through an error performance run coordi-
nated with the STC. A maximum of one error,
at any of the data rates (2.4, 4.8, 9.6, and 56 kb/s),
in each direction of data transmission during a 5-
minute interval is permitted for the DDS channel
to be acceptable. Voice coordination with the STC
is required to perform this test. This voice coordi-
nation is not over DDS, but must be via PSN.
1.04
The tests given in this section are to be per-
formed in the order given for installation test-
ing. For maintenance testing, they may be performed
individually or in any combination.
1.05
By performing the local test first, the tele-
phone company (TELCO) employee may lo-
cate a minor trouble condition without involvement
of the STC. This test ascertains the operation of the
DSU power supply and customer interface leads with
the exception of the data-set-ready lead.
NOTICE
Not for use or disclosure outside the
Bell System except under written agreement
Printed in U.S.A.
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