232XS2497 Manual
9
B&B Electronics -- PO Box 1040 -- Ottawa, IL 61350
PH (815) 433-5100 -- FAX (815) 433-5109
Smart Switch/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.
Master
Port
Preamble code controls access to slave
ports if slave handshake line is not asserted
C
Slave
Port
Port Combiner Mode
Slave
Port
B
Slave
Port
A
Handshake line of any slave
port controls access to master por
Slave
Port
D
E
Slave
Port
