Teletype SA110 Checkout And Troubleshooting

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BELL SYSTEM PRACTICES
Plant Series
SECTION 578-200-300
Issue 1, October 1970
AT&TCo Standard
PARITY FAILURE DETECTOR (SA110)
CHECKOUT AND TROUBLESHOOTING
CONTENTS
1. GENERAL
2. CHECKOUT PROCEDURE
3.
STANDARD SPEED EQUIPMENT
(33 and 35 Type Sets) .....
A. Reception of Normal Copy
B. Parity Error Detection . .
C. Significant Distortion Detection
HIGH SPEED EQUIPMENT
("DATASPEED®" Type 2 Sets)
A. Reception of Normal Data .
8. Parity Error Detection . . .
C. Significant Distortion Detection
TROUBLESHOOTING PROCEDURE
GENERAL
TROUBLESHOOTING CHART
1. GENERAL
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1.01 This section provides the checkout and trouble-
shooting procedures for the SA110 parity failure
detector and the bypass and indicator assemblies available for
use with it.
1.02 The checkout procedure is divided into two parts:
Checkout for parity failure detectors mounted on
standard speed equipment (33 and 35 type sets) and
checkout for those mounted on high speed equipment
(DATASPEED Type 2 Receivers). Since the SAllO is a
receive-only device (except for optional break generation),
access to a sending station - either remote or local - is
necessary for troubleshooting.
1.03 Because of the complexity of the parity detector
circuits, troubleshooting is confined to repairing
wired connections and replacing faulty circuit cards. It is not
considered practical to repair cards in the field. Damaged
cards should either be sent to a shop equipped to test and
replace integrated circuit packages or discarded.
2. CHECKOUTPROCEDURE
2.01 The following operational tests shou1J be made,
when required, after installation is complete. They
should also be performed after correction of any parity
detector trouble.
2.02 Refer to Part 3 for analysis of any trouble which
appears during checkout.
STANDARD SPEED EQUIPMENT (33 and 35 Type Sets)
A. Reception of Normal Copy
2.03 This test requires transmitting a test message from
an external sender to the terminal having the
SA110, either locally (over a signal line) or remotely (over
transmission lines). If a remote sender is used, transmission
errors may occur which are not detectable by the SAll0, or
which have only the parity bit -changed and so are detected
by the SAll0 as errors but appear correctly in the printed
copy. The presence of an error in the copy which was not
detected by the SAll0 or the appearance of an error
indication not accompanied by an error in the copy, then,
does not necessarily mean that a malfunction . occurred.
Should this happen, testing must be extended to determine
whether other errors will be detected or other false indica-
tions occur. If a local sender is used, no transmission errors
can occur though noise pulses from a 33 type distributor may
cause error indications at an SAll0 strapped for the
significant distortion check.
2.04 When a remote sender is used for either a 33 or 35
type set, the data connection to the terminal
should be established in. the usual manner as though the
SAll0 were not there. If there is more than one remote
sender to choose from, pick the sender most likely to have
the lowest overall error rate. This will probably be a new
sender, or one recently readjusted, located in the same city as
the SAl 10 receiver or otherwise physically as close to it as
Prepared for American Telephone and Telegraph Company by Teletype Corporation
©
1970 by Teletype Corporation
All rights reserved
Printed in U.S.A.
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