Owner`s manual

38
COMPUTER-TO-MODEL 24-TO-COMPUTER
When Computer A transmits data to Computer B through the Model 24,
the data is received from Computer A and stored in a 256-character
buffer which in turn retransmits it to Computer B. When there are only
15 bytes available in the buffer, the Model 24 will make the DTR line
low to Computer A, signaling Computer A that it cannot accept more
data. When the buffer of the Model 24 can receive more data, the
Model 24 will make the DTR line high to Computer A.
When the Model 24 retransmits the data to Computer B, the Model 24
will expect to see a high on the CTS line. When Computer B cannot
receive any more data, the Model 24 will expect to see a low on the
CTS line.
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NOTE 1: The Model 24 permits XON/XOFF to be enabled or disabled
by port independently in the receive and transmit directions. The
description of handshaking functions below considers XON/XOFF to be
enabled in both directions. If XON/XOFF is disabled in one direction,
that direction will support hardware handshaking as described in
Section 6.5.1 of this manual.
NOTE 2: When XON/XOFF is enabled in the receive direction, the DTR
line will always remain high and will not be used as a handshaking line.
NOTE 3: If the Model 24 receives an XOFF, it must receive an XON to
restart sending data. If the CTS is low then it will expect to see the
CTS high. A low CTS and an XOFF or vice versa can not be mixed.