47
+
IBM
3
2
7
D
B
2
5
IBM - PC
+ 5 V
10 µF, 16 V 10 µF, 16 V
10 µF, 16 V
+
15 8
Rx
Tx
Ground
IBM
IBM
Tx
Rx
6 2 16 10
11
12
14
13
1
3
4
5
+
+
10 µF, 16 V
10 µF, 16 V
ICL 232
TSC 232
Tx
Rx
+ 5 V
Mini-Din
TTL to RS 232 converter
15.3 Communication protocol
The exchange of information when a OSP is interconnected with a PC is as it follows.
Serial Interface of PC has to be set to 9600 Baud, 8 bit and No parity.
15.3.1 Computer data request from OSP to PC
Computer OSP
Tx IDNAME →Rx IDNAME Proceed if the name is acknowledged
Rx IDNAME ←Tx IDNAME If not, do not answer
Tx Instruction →Rx Instruction
Rx Instruction ←Tx Instruction
Tx char →Rx char
Rx DATA 1 ←Tx DATA 1
Tx char →Rx char
Rx DATA 2 ←Tx DATA 2
Tx char →Rx char
Rx DATA 3 ←Tx DATA 3
Tx char →Rx char
Rx DATA 4 ←Tx DATA 4
Tx CHKSUM →Rx char
Rx CHKSUM ←Tx CHKSUM
IDNAME, Instruction, DATA 1, DATA 2, DATA 3, DATA 4 and CHKSUM are 8-bit values (1 byte)
Tx CHKSUM = DATA 1+DATA 2+DATA 3+DATA 4 .AND. FF
Rx CHKSUM = DATA 1+DATA 2+DATA 3+DATA 4 .AND. FF
The above is useful to verify correct received data.
The minimum time-out of OSP is 3 seconds.
IDNAME is set to 1.