C9900-E188 with 1 serial interface RS485
The interface contains an electrically isolated socket. It is led out via a 9-pin standard DSUB connector. The interface provides an asynchronous, serial communication method defined in the RS485 standard.
The channel features overvoltage protection.
Fig.15: RS485 interface pin numberingPin | Signal | Type | Description |
|---|---|---|---|
1 | N/C | - | Not used |
2 | TxD + | Data-Out + | Transmit 485 |
3 | RxD + | Data-In + | Receive 485 |
4 | N/C | - | Not used |
5 | GND | Ground | Ground |
6 | VCC | VCC | +5 V |
7 | TxD- | Data-Out - | Transmit 485 |
8 | RxD- | Data-In - | Receive 485 |
9 | N/C | - | Not used |
10 | N/C | - | Not used |
Pins 2 and 3 (data +) and pins 7 and 8 (data -) must be connected.
On delivery the interface is configured as a half-duplex endpoint without echo as standard – see table below:
Function | Status |
|---|---|
Echo | off |
Auto send | on |
Always send | off |
Auto receive | on |
Always receive | off |
Termination | on |