B&B Electronics 232MSS2 - Manual (Page 13)

Documentation Number 232MSS2-0108 Manual 9
B&B Electronics Mfg Co Inc – 707 Dayton Rd - PO Box 1040 - Ottawa IL 61350 - Ph 815-433-5100 - Fax 815-433-5104
B&B Electronics Ltd – Westlink Commercial Park – Oranmore, Galway, Ireland – Ph +353 91-792444 – Fax +353 91-792445
A typical application would be to have RTS and CTS tied
together on the master port. When RTS (assuming DTE slave port)
on port A 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 232MSS2 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 232MSS2 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 232MSS2 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 232MSS2 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 232MSS2 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 232MSS2 it is the set timer value command and the
“6” indicates which timer value to use.