Multi-Tech Systems FR111 - Manual (Page 73)

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The Word Length option sets the number of bits in a word. The word
length range is 5 to 8 bits. The default is 8 bits.
The Stop Bits option sets the number of stop bits. The number of stop
bits can be 1, 1.5, or 2. The default is 1 bit.
The Parity option sets parity for odd, even or none. Under normal
conditions, parity is set to none. The default is none.
The Flow Control option allows for two types of flow control: the soft-
ware-based XON/XOFF and the hardware-based Clear to Send (CTS).
The default condition is CTS. Flow control is the means by which data
flow from the device into the MultiFRAD is controlled. Flow control is
necessary when the data handling capacity of the data port cannot keep
up with the volume of data sent to it. When the data device controls data
flow to itself, it is called pacing (see Pacing option). The combination of
flow control from the port device and pacing to the data device is how
data transfers are regulated so that no data is lost.
DATA DATA
Channel
Device Channel
Device
CHANNEL DEVICE-
INITIATED PACING
Pacing stops the output of
data from the MultiFRAD Flow control stops the input
of data to the MultiFRAD
MultiFRAD-INITIATED
FLOW CONTROL
MultiFRAD MultiFRAD
The Enq/Ack Flow Control option is a special flow control protocol used
in Hewlett Packard computer systems. This option is sometimes
referred to as Enquire/Acknowledge flow control because it’s based on
the computer sending an enquiry (ENQ) and then expecting an ac-
knowledgment (ACK). The default condition for this option is off.
The Echo option enables data entered on the data device keyboard to
be returned to the device's monitor. The purpose of this option is so that
an operator will not experience undue delays in seeing entered data
appear on their monitor. The default condition for the echo option is off.
The Pacing option controls the data flow to the data device. This option
only applies to the async mode of operation. Pacing is necessary when
the flow of data to a device operating on the data port is more than it can
process. If the device cannot process the volume of data sent to it, then
the pacing option should be turned on. The pacing method used is
determined by the type of flow control. The default condition is for this
option to be turned off.