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Error (ER) -
All Models
Ring (RR) -
70/720-11,21,22
END - All Models
END and Error
(EER) - All Models
Break Detected
(BDR)
70/720 Asynchronous
Data Set Buffer
• When a command is present in the buffer but after an RDY (except
where noted or during automatic calling) and prior to END, the buffer
indicates an error condition to the CCM via an Error Report (ER).
An
ER
is caused by the following:
1.
Transmit - Loss of the data set CTS signal, prior to END.
2.
Receive - LossofthedatasetDCDsignal,priortoreceipt of TERC.
*3.
Auto -Call - A signal from the Auto-Call special feature.
The buffer reports such conditions once per occurrence.
If
error and malfunction conditions occur simultaneously, only the MR
is indicated to the CCM.
• The buffer is always conditioned to detect an RI signal from the data set
and report a Ring (RR) to the CCM. The buffer reports a Ring only once per
RI signal from the data seto The Ring Report, as well as the RI signal from
the data set, do not apply to the 70/720-23 Buffer, or to the 70/720-21 and
22 Buffers when used with private line applications.
•
The buffer reports END whenever it completes the operations required
by each command as previously indicated. END is enabled by a TERC or a
DISC from the CCMo
•
The buffer indicates a concurrent END and error condition by means of
the END and Error Report (EER)o When using the 70/720-23 Buffer, EER is
caused by the sensing of 14 ms. of spacing on the RD lead from the data
seto
• When a TC is present in the Buffer, but after an RDY and prior to END,
the buffer indicates a reverse channel signal detected to the CeM via BDR.
BDR is caused by the following:
Model 70/720-11- upon detecting RD spacing continuously for X ms.
Model 70/720-21 - not applicable to this buffer.
Model 70/720-22 - upon detecting:
1.
RD spacing continuously for
X
ms; or optionally
20 SRD
OFF
for
X
ms; or optionally
3. Reverse channel implementation option
4.
X
is normally set to 50 ms but may be set to any point in the
range of :20-115 ms.
Model 70/720-23 - upon detecting RD spacing continuously for 140ms.
*The Auto-Call signal does not apply to the 70/720-23 Buffer, or to the
70/720-21
and
22
Buffers when used with private line applicationso
4-19
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