Chapter 3Hardware
Serial B Interface (J3A/B)
Table
Pin # | Pin # | Signal | Description |
| DB9 |
|
|
A1 | 1 | DCD3* | Data Carrier Detect 3 – Indicates external serial communications device |
| (COM3) |
| is detecting a carrier signal (i.e., a communication channel is currently |
|
|
| open). In direct connect environments, this input will be driven by |
|
|
| DTR3 as part of the DTR/DSR handshake. |
A2 | 6 | DSR3* | Data Set Ready 3 – Indicates external serial communications device is |
|
|
| powered, initialized, and ready. Used as hardware handshake with |
|
|
| DTR3 for overall readiness to communicate. |
A3 | 2 | RXD3 | Receive Data 3 – Serial port 3 receive data in. |
|
| RX3- | RX3- – If in RS485 or RS422 mode, this pin is Receive Data 3 |
|
|
|
|
A4 | 7 | RTS3* | Request To Send 3 – Indicates Serial port 3 is ready to transmit data. |
|
|
| Used as hardware handshake with CTS3 for low level flow control. |
|
| TX3+ | TX3+ – If in RS485 or RS422 mode, this pin is Transmit Data 3 +. |
|
|
|
|
A5 | 3 | TXD3 | Transmit Data 3 – Serial port 3 transmit data out. |
|
| TX3- | TX3- – If in RS485 or RS422 mode, this pin is Transmit Data 3 |
|
|
|
|
A6 | 8 | CTS3* | Clear To Send 3 – Indicates external serial communications device is |
|
|
| ready to receive data. Used as hardware handshake with RTS3 for low |
|
|
| level flow control. |
|
| RX3+ | RX3+ – If in RS485 or RS422 mode, this pin is Receive Data 3 +. |
|
|
|
|
A7 | 4 | DTR3* | Data Terminal Ready 3 – iIndicates Serial port 3 is powered, initialized, |
|
|
| and ready. Used as hardware handshake with DSR3 for overall |
|
|
| readiness to communicate. |
A8 | 9 | RI3* | Ring Indicator 3 – Indicates external modem is detecting a ring |
|
|
| condition. Used by software to initiate operations to answer and open |
|
|
| the communications channel. |
A9 | 5 | GND | Ground |
|
|
|
|
A10 | NC | NC | Not connected/Key |
B11 | 1 | DCD4* | Data Carrier Detect 4 – Indicates external serial communications device |
| (COM4) |
| is detecting a carrier signal (i.e., a communication channel is currently |
|
|
| open). In direct connect environments, this input will be driven by |
|
|
| DTR4 as part of the DTR/DSR handshake. |
B12 | 6 | DSR4* | Data Set Ready 4 – Indicates external serial communications device is |
|
|
| powered, initialized, and ready. Used as hardware handshake with |
|
|
| DTR4 for overall readiness to communicate. |
B13 | 2 | RXD4 | Receive Data 4 – Serial port 4 receive data in. |
|
| RX4- | RX4- – If in RS485 or RS422 mode, this pin is Receive Data 4 |
|
|
|
|
B14 | 7 | RTS4* | Request To Send 4 – Indicates Serial port 4 is ready to transmit data. |
|
|
| Used as hardware handshake with CTS4 for low level flow control. |
|
| TX4+ | TX4+ – If in RS485 or RS422 mode, this pin is Transmit Data 4 +. |
|
|
|
|
B15 | 3 | TXD4 | Transmit Data 4 – Serial port 4 transmit data out. |
|
| TX4- | TX4- – If in RS485 or RS422 mode, this pin is Transmit Data 4 |
ReadyBoard 700 | Reference Manual | 41 |
