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Documentation Number 232BSS4-2907m
B&B Electronics Mfg Co Inc – 707 Dayton Rd - PO Box 1040 - Ottawa IL 61350 - Ph 815-433-5100 - Fax 815-433-5104 – www.bb-elec.com
B&B Electronics – Westlink Commercial Park – Oranmore, Galway, Ireland – Ph +353 91-792444 – Fax +353 91-792445 – www.bb-europe.com
Auto Select/Smart Switch Mode
Description
Auto Select mode allows the Slave devices to initiate communications
with the device connected to the Master port. When Auto Select mode is
enabled through the setup software, the 232BSS4 passes data automatically
from the Slaves to the Master.
Each Slave port is buffered until the Master is available, then sent in
turn. At any time, the Master can reply to the Slaves using the Send to
Specific Ports command, or override the automatic switching by selecting a
specific port for both transmit and receive.
When the Master device releases the Slave through the Turn Off all
ports command, the automatic switching resumes. The 232BSS4 will revert
back to the Slave port that was sending data before the Master took over or
to the next sequential Slave port with data in its buffer. For a full
description of the 232BSS4 commands, refer to the previous section,
“Smart Switch Only Mode.”
Options
Initial Connections:
Upon power-up, the 232BSS4 can be initialized to allow the Master
to send data to any of the Slave ports without any commands sent. The
Master can also be set to broadcast to any or all of the Slave ports on
power-up. This allows the switch to be used to add devices to an
existing COM port without any software programming. The port
initialization is configured through the setup software.
Timeouts:
When multiple Slave devices are sending data to the Master port at
the same time, the 232BSS4 must determine when to stop sending from
one Slave port and switch to the next. Two parameters are required to
be entered in the setup software for Auto Select mode. The Port Time
and Inactivity Time tell the 232BSS4 how much time to spend on each
port, and how long a port must be inactive before switching to the next
port.
Port Time:
Setting the Port Time for a value other than zero configures the
Master device to receive data from a single port only for the length of
time specified during setup. Times are set in milliseconds and can be
anywhere in the range of 0 to 65,000 (65 seconds). A value of zero for
the Port Time would give the transmitting Slave port access to the
Master until an Inactivity Timeout was reached or until a specific Turn
Off command was sent from the Master device.
