B&B Electronics Five Port Expandable Smart Switch, 232XS5 Enhanced Timer Mode -- Timer Features

NOTE: When a port is selected via the Master Port, the RTS lines will be ignored until the Master Port sends the turn off code. When the Master Port is selected by RTS, all preamble codes will be ignored. The port combiner function is not available with the Master Port configured as a DCE or in expansion mode.

A typical application would be to have RTS and CTS tied together on the master port. When RTS 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 Timer Mode -- Timer Features

The 232XS5 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 232XS5 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 232XS5 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 jumper setting and through software commands. Jumper JP6-A must be OFF (removed) for the 232XS5 to be in enhanced mode. The software commands follow the same format as preamble codes used for switching. There are two commands that must be sent to the 232XS5 to set the timer functions: Set Timer Value and Set Timer Mode. 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. The time set by the Set Timer Value command determines the length of time the 232XS5 wll wait before disconnecting an inactive port, or the length of time it will ignore switching commands from the master. Refer to Table 7 for timer values. For example, sending the following string to the 232XS5 will set the timer value to 5 seconds (assuming programmable character is the factory default of 2).

10	232XS53800 Manual
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