232SS21600Manual 9
B&B Electronics Mfg Co Inc – 707 Dayton Rd - PO Box 1040 - Ottawa IL 61350 - Ph 815-433-5100 - Fax 815-433-5104
A typical application would be to have RTS and CTS tied together
on the master port. When RTS (assuming DTE slave device) on port
A (configured as DCE) is asserted, CTS on port A will be asserted
when a connection is established. If a port is not connected to the
master port, then CTS on that port will remain low. Therefore, a port
can monitor the handshake line to determine if a connection has
been established.
Enhanced Mode -- Timer Features
The 232SS2 has an enhanced mode, which offers special timer
features. The timer features can be used to prevent slave devices
from receiving preamble commands, inadvertent switching from
binary/graphic file transfers, and inactive slave devices from holding
control of the master port. The timer has two different modes: an
inactivity mode and an inadvertent switch mode. When in inactivity
mode, the 232SS2 will monitor the data lines. If there is no activity
for the specified time, the selected slave port will be disconnected
from the master port. When in inadvertent switch mode, the
232SS2 will ignore switching commands for the specified period of
time. After this time has expired, the selected slave port will be
disconnected from the master port.
The timer functions are enabled via a dipswitch setting and
through software commands. Dipswitch SW1 position 4 must be
ON for the 232SS2 to be in enhanced mode. The software
commands follow the same format as preamble codes used for
switching. There are two commands used to set the timer functions:
Set Timer Mode and Set Timer Value. These commands require an
additional byte for data. The Set Timer Value command requires the
third byte to be an ASCII “T” character. The data byte (fourth byte)
must be a value between ASCII “0” and ASCII “9”. A value of “0” is
used to disable the timer. Refer to Table 3 for timer values. For
example, sending the following string to the 232SS2 will set the
timer value to 5 seconds (assuming programmable character is the
factory default of 2).
SetTV$ = CHR$(27) + CHR$(2) +”T” + “6”
The “T” tells the 232SS2 it is the set timer value command and the
“6” indicates which timer value to use.