RS-232
From uCtrl.net
Contents |
Information
RS-232 is the standard used in computer serial ports. It only allows for two points, a master and a slave. It uses voltage levels between +12V and -12V, but requires the receiver to distinguish voltages as low as +3V and -3V. Some manufacturers therefore built transmitters that supplied +5V and -5V and labeled them as "RS-232 compatible."
- Mode of Operation
- Single-ended
- Total number of receivers and drivers on one line
- 1 receiver, 1 driver
- Maximum cable length
- 15 meters (50 feet)
- Maximum data rate
- 20kb/s
- Maximum driver output voltage
- +/-25V
- Driver output signal level
- +/-5V to +/-15V (loaded) - +/-25V (unloaded)
- Driver load impedance
- 3k to 7k ohms
- Maximum driver current in high Z state
- +/-6mA @ +/-2v (power off)
- Maximum slew rate
- 30V/uS
- Receiver input voltage range
- +/-15V
- Receiver input sensitivity
- +/-3V
- Receiver input resistance
- 3k to 7k ohms
Pin-out
| Signal Type | Abbr. | Dir. | DB-25 | DE-9 |
|---|---|---|---|---|
| Common Ground | G | – | 7 | 5 |
| Transmitted Data | TxD | Out | 2 | 3 |
| Received Data | RxD | In | 3 | 2 |
| Data Terminal Ready | DTR | Out | 20 | 4 |
| Data Set Ready | DSR | In | 6 | 6 |
| Request To Send | RTS | Out | 4 | 7 |
| Clear To Send | CTS | In | 5 | 8 |
| Carrier Detect | DCD | In | 8 | 1 |
| Ring Indicator | RI | In | 22 | 9 |
Images
 Pin config |
 Handshake |
 Serial link |
