Windows CE–based devices use the RS-232-C standard to exchange data with serial devices and other computers by way of a serial connection.
When a serial connection is established between two devices, an application designates one device as the Data Communications Equipment (DCE) and the other device as the Data Terminal Equipment (DTE). The following table shows pin locations and describes common pin functions used on 9-pin and 25-pin connectors.
9-pin |
25–-pin |
Purpose |
Description |
| 3 | 2 | TD Transmit data |
Sends data to another device |
| 2 | 3 | RD Receive data |
Receives data from another device |
| 7 | 4 | RTS Request to send |
Indicates the device is ready to send data |
| 8 | 5 | CTS Clear to send |
Indicates the device is ready to accept data |
| 6 | 6 | DSR Data set ready |
Indicates the receiving device is connected and ready to accept data |
| 5 | 7 | GND Signal ground |
Verifies both devices are using the same voltage for transmitting data |
| 4 | 20 | DTR Data terminal ready |
Indicates that the DTE device is ready |
Windows CE–based devices use cables with a mini-connector, 9-pin connector, or 25-pin connector. Each connector is discussed in the following sections.