B&B Electronics 232XS5 User Manual

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232XS2497 Manual 
 
13 
B&B Electronics  --  PO Box 1040  --  Ottawa, IL  61350 
PH (815) 433-5100  --  FAX (815) 433-5109
 
Expansion Mode 
 
 
The number of serial ports on the 232XS5 can easily be 
expanded to a maximum of seventeen ports.  Up to four 232XS5 
units may be cascaded in expander mode.  Each unit address adds 
four additional serial ports to the five on unit address “A”.  Port C is 
used as the expansion port that connects to the follow-on master-
port for switch units addressed “B” thru “D”.  Expansion Switch unit 
address “A” is the last Switch in the chain. 
 
 
Expander mode is selected when jumper “JP6-B” is OFF 
(removed.)  In Expander mode, the 232XS5 is constantly looking for 
a four character preamble code by monitoring the data that is being 
received on the master port from the host device.  The 232XS5 
requires a four character preamble code to turn on and off a port.  
The first character must be the ASCII escape character (decimal 
27).  The second character is user programmable by setting 
dipswitch “SW2”.  “SW2” comes from the factory programmed to the 
ASCII character STX (decimal 2).  The third character is the 
Expansion Switch Unit Address character “A” through “D”.  The 
fourth character should be the ASCII upper case letters "A", "B", "C", 
"D" or “E” (decimal 65, 66, 67,  68 or 69 respectively) to select those 
ports.  To turn off the selected port the third character should be the 
ASCII EOT character (decimal 4).  For instance, to turn on port B of 
Expansion Switch unit address C, you would send: 
 
ESC STX C B 
 
 
If you were writing a program in BASIC to control the Smart 
Switch you would form a string like this: 
 
SWB$ = CHR$(27) + CHR$(2) + "C" + ”B” 
 
Master
Port
Expansion
Port
17-Port Cascaded Expansion Mode
Address D
C
C
Address C
Slave
Port
B
Slave
Port
A
Slave
Port
A
Address B
Slave
Port
Slave
Port
A
B
Slave
Port
B
C
Slave
Port
D
E
Slave
Port
E
Slave
Port
Expansion
Port
E
Slave
Port
D
Slave
Port
Expansion
Port
Slave
Port
D
C
Slave
Port
Slave
Port
Slave
Port
Address A
A
B
E
D
Slave
Port
Slave
Port