Computer Communication
Technical Handbook
019722-101 Rev. 05
77
SC-350/360
12 Computer Communication
12.1 Serial Interface
The communication is carried out via an RS232C interface where
SC 350/360 is classified as Data Terminal Equipment (DTE). The
data format is 9,600 baud, 8 bits, no parity bit and one stop bit.
SC 350/360 works as a slave, that is only the computer can take the
initiative to perform any data exchange with the machine. The
exchanges are controlled by hardware handshaking signals. The
required cable connections are:
12.2 Protocol Structure
Note!
In the following protocol descriptions two logical operators are used,
+ for arithmetic addition and ^ for logical AND.
All messages have the following principal structure:
If the data is a binary number, the most significant byte (character) is
sent first. If the data is a text string, the first character of the string is
sent first. A text string always ends with a NULL character.
>>>
Signal name
SC 350/360
pin no.
Signal
direction
Computer (PC)
pin no. (25-pin)
Computer
pin no.(9-pin)
Shield
1
<––––––>
1
-
TxD
2
–––––––>
3
2
RxD
3
<–––––––
2
3
CTS
5
<–––––––
4
7
Ground
7
<––––––>
7
5
RTS
20
–––––––>
5
8
Computer (PC)
SC-350/360
–––––––>
ESC (message start)
–––––––>
Command
<––––––>
Data (direction depends on command)
<––––––>
Check sum (direction depends on command)
<–––––––
Receipt:
- ACK (if check sum is correct) or
- NAK (if check sum is incorrect)
