Dataset Hardware Flow Control; Compatibility; Printer Connecting Cables - Mitel SX-200 Practices

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16
' DATASET HARDWARE FLOW
CONTROL
F!QW Control
16.1 The dataset is designed to conform to the RS-232C specificat.ion. However,
RS-232C does not define a control lead for DTE flow control of:a DCE device.
,
Several printer manufacturers use Pin 20 (DTR) for this purpose; others use Pin 11
and/or other RS-232 leads for flow control purposes. Some manufacturers force a
lead high to indicate a flow controlled state, while others force a lead low. A standard
has not been defined.
In order to fully support devices which use only hardware flow control, pin 25 may be
programmed in CDE to be used by an attached device to flow control the dataset. Pin
25 may also be used as a Ring Indicator (RI) input to the dataset, to signal an incoming
call when a modem is attached to the dataset. Pin 25 does not have to be explicitly
defined in CDE as an RI input; the data set assumes this use unless the Pin 25/CTS
flow control option is selected. This implies that hardware flow control of the dataset and
incoming modem calls are mutually exclusive.
The flow control options available through CDE are:
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XON/XOFF.
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CTS - The dataset flow controls the attached device by dropping CTS; the device
cannot flow control the dataset.
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None.
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Pin 25 High/CTS -The attached device flow controls the dataset by raising Pin 25,
the dataset flow controls the device by dropping CTS.
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Pin 25 Low/CTS -The attached device flow controls the dataset by dropping Pin
25, the dataset flow controls the device by dropping CTS.
Compatibility
Datasets supporting the new hardware flow control options are compatible with older
versions of PABX software; however, pin 25 flow control will not be available.
Older datasets can also be used with new PABX sofbvare; however, selecting the pin
25 flow control options in CDE will have no effect.
Printer Connecting Cables
16.2 Cables which support three common methods of hardware flow control are described
following. Data Circuit Descriptors are described in the Customer Data Entry (CDE)
Practice of the associated PABX.
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