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.
Documentation Number | 9 |
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