Chapter 3 | Hardware |
Table
Pin # | Pin # | Signal | Description |
| DB9 |
|
|
1 | 1 | DCD1* | Data Carrier Detect 1 – Indicates external serial communications device |
| (COM1) |
| is detecting a carrier signal (i.e., a communication channel is currently |
|
|
| open). In direct connect environments, this input will be driven by DTR1 |
|
|
| as part of the DTR/DSR handshake. |
2 | 6 | DSR1* | Data Set Ready 1 – Indicates external serial communications device is |
|
|
| powered, initialized, and ready. Used as hardware handshake with DTR1 |
|
|
| for overall readiness to communicate. |
3 | 2 | RXD1 | Receive Data 1 – Serial port 1 receive data in. |
|
| RX1- | RX1- – If in RS485 or RS422 mode, this pin is Receive Data 1 |
4 | 7 | RTS1* | Request To Send 1 – Indicates Serial port 1 is ready to transmit data. |
|
|
| Used as hardware handshake with CTS1 for low level flow control.. |
|
| TX1+ | TX1+ – If in RS485 or RS422 mode, this pin is Transmit Data 1 +. |
|
|
|
|
5 | 3 | TXD1 | Transmit Data 1 – Serial port 1 transmit data out. |
|
| TX1- | TX1- – If in RS485 or RS422 mode, this pin is Transmit Data 1 |
|
|
|
|
6 | 8 | CTS1* | Clear To Send 1 – Indicates external serial communications device is |
|
|
| ready to receive data. Used as hardware handshake with RTS1 for low |
|
|
| level flow control. |
|
| RX1+ | RX1+ – If in RS485 or RS422 mode, this pin is Receive Data 1 |
7 | 4 | DTR1* | Data Terminal Ready 1 – Indicates Serial port 1 is powered, initialized, |
|
|
| and ready. Used as hardware handshake with DSR1 for overall readiness |
|
|
| to communicate. |
8 | 9 | RI1* | Ring Indicator 1 – Indicates external serial communications device is |
|
|
| detecting a ring condition. Used by software to initiate operations to |
|
|
| answer and open the communications channel. |
9 | 5 | GND | Ground |
|
|
|
|
10 | NC | KEY/ | Key |
|
| NC | Not connected |
|
|
|
|
11 | 1 | DCD2* | Data Carrier Detect 2 – Indicates external serial communications device |
| (COM2) |
| is detecting a carrier signal (i.e., a communication channel is currently |
|
|
| open). In direct connect environments, this input will be driven by DTR2 |
|
|
| as part of the DTR/DSR handshake. |
12 | 6 | DSR2* | Data Set Ready 2 – Indicates external serial communications device is |
|
|
| powered, initialized, and ready. Used as hardware handshake with DTR2 |
|
|
| for overall readiness to communicate. |
13 | 2 | RXD2 | Receive Data 2 – Serial port 2 receive data in |
|
| RX2- | RX1- – If in RS485 or RS422 mode, this pin is Receive Data 2 |
|
|
|
|
14 | 7 | RTS2* | Request To Send 2 – Indicates Serial port 2 is ready to transmit data. |
|
|
| Used as hardware handshake with CTS2 for low level flow control. |
|
| TX2+ | TX2+ – If in RS485 or RS422 mode, this pin is Transmit Data 2 +. |
15 | 3 | TXD2 | Transmit Data 2 – Serial port 2 transmit data out |
|
| TX2- | TX2- – If in RS485 or RS422 mode, this pin is Transmit Data 2 |
44 | Reference Manual | LittleBoard 550 |