4. INTERFACE SPECIFICATIONS
4.1 Serial port (RS232C)
4.1.1 Serial port (RS232C) communication
(a) This interface specification is based on EIA RS232C baud rate 300 to 38400 BPS,
8 data bits, none parity, 1 or more stop bits
(b) Serial port (RS232C) communication data link
Data link flow chart:
PC/HOST display display printer printer PC/HOST
Control for RTS and DTR :
PC/HOST display display printer printer PC/HOST
(c) CD7220 will activate DTR or RTS signal to PC/host in the following two conditions:
1. Printer will activate DTR or RTS signal.
2. The pass through buffer in CD7220/CD3220 is full ( 200 bytes ) .
* If PC/host keep transmitting the data to printer when CD7220/CD3220 activate DTR or RTS, the data will be lost.
4.1.2 Serial port interface for rectangle basic section
(a) Serial port interface connector position for rectangle basic section