Owner`s manual

When the Model 24H retransmits the data to the host device and the

host device can no longer accept data, the Model 24H will expect to

detect a false condition on the host port's CTS line. When the host

device can accept more data, the Model 24H will expect to detect a true

condition on the CTS line.

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The Model 24H 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 5.5.1

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. When

transmitting data and the Model 24H receives an XOFF character, it

must receive an XON character and detect a true condition on the CTS

line to restart sending data.

NOTE: When sending binary data and using XON/XOFF handshaking,

the input flow control (Recv) of the respective port should be enabled

and the output flow control (Xmit) should be disabled. This will allow

any binary character with the same bit pattern as XON or XOFF to be

passed to the receiving device.

Host-to-Model 24H-to peripheral communication:

When the host device transmits data to the Model 24H host port, the

data is received and stored in a 426 character buffer which in turn

retransmits it to a selected peripheral device through a peripheral port.

During transmission, when there are only 19 bytes available in the

buffer, the Model 24H will send an XOFF character, signaling the host

device that it cannot accept more data. When the buffer of the Model

24H can receive more data, the unit will send an XON character.