RCA 70/700 Series Reference Manual page 87

Buffer Options
(Cont'd)
Communication
Equipment
Options
70/720 Asynchronous
Data Set Buffer
Reverse Channel Signal Detection Model 70/720-22 - This function
effective during transmission for break signal detection with some tele-
typewriter systems and for detection of reverse channel error and channel
assurance signals. The operation of this function is as follows:
After receipt of a TC, transmission cannot start until RD is marking (or,
optionally, SRD is on) continuoU[::,I!v for Xms.While transmitting, a break
detected is reported if RD goes spacing (or, optionally, SRD is off) con-
tinuously for Xms. The buffer then inhibits RDY while RD is spacing, but
transmits the bits already received from the CCM. When RD returns to
the marking condition, transmission is resumed.
The X ms duration of the reverse signal is adjustable. It is normally set
to 50 ms, but it may be set to any point in the range of 20 to 115 mso
Reverse Channel Signal Generation - Model 70/720-22, Only -
This function is effective during reception for generation of reverse channel
error and channel assurance signals. The effect of the option is as follows:
After receipt of anRC, the buffer turns STD ono Upon termination (TERC)
of an RC, the buffer turns STD off (or, optionally, TD spacing) forYms,
then it responds to a SEL with END and returns TD marking.
1. Y is normally set to 200 ms, but may be set to any point in the range:
115-750 ms.
2. This causes END to be delayed for Y ms after TERC for both the TC
and the ACC as well as the RC.
Data Gathering System (DGS) -Model 70/720-22, Only - This option
enables the buffer and associated data set (AT&T 202D or equivalent) to
communicate with a Data Gathering System Input Station via a Line Concen-
trator. The effect of this option is as follows:
DTR is strapped on. RS is strapped ono After receipt of an RC, the
buffer turns TD on. TD is on until RC is terminated whereupon it is
turned off. This option may only be used with four-wire private line
facilities.
• At installation, the data set must be conditioned (by the common carrier
upon request) as follows:
AT&T 103A DataSet - Automatic Answer - controlled by AUTO key.
Initiate Disconnect - Yes.
Respond to Disconnect - No.
AT&T 103F DataSet - Mode-local: Originate, remotes: Answer; at all
times.
AT&T 202C Data Set - Automatic Answering - controlled by A UTO key.
AT&T 202D Data Set - Two or four-wire operation o
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