B&B Electronics 232XS5 Smart Switch/Port Combiner Mode, Enhanced Timer Mode -- Timer Features

Smart Switch/Port Combiner Mode

Slave Slave

Port Port

Port Combiner Mode

With the 232XS5 set up with a DTE master port, this mode allows Slave Ports A-E to select the master port using the RTS input line. It also still allows selection from the master port via the preamble code described in the Smart Switch Only Mode section. Jumper “JP6-C” must be OFF (removed) to be in port combiner mode. Port combiner mode is not accessible when the unit is set up as a port expander, so JP6-B must be ON (installed). When RTS goes high on any of the five slave ports, it will establish a connection from that port to the master port. This works on first-come-first- served basis. If multiple ports have their RTS lines high, the port that has been waiting the longest will be next to be connected to the master port. For example (initial conditions -- no slave ports with RTS lines asserted.), in chronological order, Port C asserts its RTS line, Port A asserts its RTS line, Port D asserts its RTS line and then Port C disasserts its RTS line. When Port C asserts its RTS line, a connection will be made between the master port and Port C. When Port C disasserts its RTS line, Port C will be disconnected and Port A will be connected to the master port. When Port A disasserts its RTS, Port A will be disconnected and Port D will be connected to the master port.

For example, port A is configured as a DTE port. In order to establish a connection to the master port, port A must set RTS high (assert). The 232XS5 would recognize this as a prompt for connection to the master port. The connection would be dropped as soon as RTS on port A is brought low. Ports B-E may raise RTS at any time to request a connection. However, if port A is connected to the master port, any data sent from the devices on ports B-E to the 232XS5 will be lost. The 232XS5 does not have any buffering.

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

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).

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