Interfejs pro komunikaci 
27.5.2003
Popis konektoru sériového portu PC
| Description | Signal | 9-pin DTE | 25-pin DCE | směr z hlediska PC |
|---|---|---|---|---|
| Carrier Detect | CD | 1 | 8 | vstup |
| Receive Data | RD | 2 | 3 | vstup |
| Transmit Data | TD | 3 | 2 | výstup |
| Data Terminal Ready | DTR | 4 | 20 | výstup |
| Signal Ground | SG | 5 | 7 | vstup |
| Data Set Ready | DSR | 6 | 6 | vstup |
| Request to Send | RTS | 7 | 4 | výstup |
| Clear to Send | CTS | 8 | 5 | vstup |
| Ring Indicator | RI | 9 |
22 |
vstup |
| Canon 25 | Canon 9 | z pohledu PC | ||
|---|---|---|---|---|
| 1 | - | PGND | Protective Ground | |
| 2 | 3 | TXD | Transmit Data | The modem receives data from de PC. |
| 3 | 2 | RXD | Receive Data | The modem transmits data to the PC |
| 4 | 7 | RTS | Ready To Send | The PC sets this signal when has a character ready to be sent. |
| 5 | 8 | CTS | Clear To Send | The modem is ready to transmit data. The computer will start sending data to the modem. |
| 6 | 6 | DSR | Data Set Ready | The modem tells the PC it is powered up and ready to transmit or receive data |
| 7 | 5 | SG | Signal Ground | |
| 8 | 1 | CD | Carrier Detect | The modem sets this signal when has detected the computer |
| 20 | 4 | DTR | Data Terminal Ready | The PC tells the modem that is powered up and ready to send data. |
| 22 | 9 | RI | Ring Indicator | |
RS232 definuje:
- Signal = 0 (LOW) > +3.0V
- Signal = 1 (HIGH) < -3.0V
(zveřejněno na stránce Kabely)