User`s manual

Data Options and Profiles
If it does, eia flow control will be required. Note, however, that not all computer
interfaces support eia flow control.
If your PC does not support eia flow control, you will have to set the flow control
options to off and ensure that flow control is not required. That is,
both endpoints must operate at the same speed and the speed cannot exceed
the effective throughput capability of the data channel. (Even if these
requirements are met, continuous file transfer without pauses can still fail
because the speed of both endpoints are not exactly the same. This may result
in buffer overflow at the receiving end.)
For D-channel packet data transmission, the effective throughput capability
varies depending on network loading, but cannot exceed 18 kbps of
asynchronous data. Therefore, for DX25 mode, you must not set the speed of
the endpoints greater than 9.6 kbps. Under significant network loading, the
effective throughput capability may drop below this level and result in lost data.
For Mode 2 protocol, the maximum effective throughput capability is 19.2 kbps of
asynchronous data, therefore you must not set the endpoint speeds greater than
19.2 kbps. For Mode 3 and the V.120 modes, the effective channel throughput
capability varies among endpoints but should be greater than
19.2 kbps. For these data modes, you may or may not be able to successfully
transfer files at speeds as high as 38.4 or 57.6 kbps.
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