Owner`s manual

133
15.2V50/V73/V74/V75/V76/V86/87
OPERATING IN THE DIFFERENT MODES
A typical application using a
V50/V73/V74/V75/V76/V86/V87 module would have a
host computer such as an IBM PC connected to the host
module and various devices such as cash registers,
digital laboratory instruments, bar code readers,
numerical machines, printers, modems, terminals, etc.
connected to the serial ports.
Regardless of the mode of operation, any terminal
connected to a V71 host module can connect and send
data to a specific port by sending the appropriate port
select sequence followed by the data. A port select
sequence consists of the port select code (default is
$BT), the desired Unit Number followed by a colon (1: to
30: - only if using cascaded units), the desired module
number (2 to 16), a comma, the desired port number (1
to 4), and a terminating character (0A Hex - Carriage
Return or 0D Hex - Line Feed). The port select
sequence is not passed through to the selected port.
NOTE: When the host computer/controller selects an
EIA-485 port on a V87 module, all characters sent to the
peripheral device are echoed back to the host device.
Full duplex reporting mode provides bidirectional
communication between the host computer and the
selected peripheral device. Data received by non-
selected peripheral ports is buffered until selected by
the host computer.
Immediate message mode provides automatic message
multiplexing and is discussed in Section 15.2.2. A
message begins when a port on the module receives a
character from the device connected to it. A message is
completed when the message terminating character is