Promi SD205-OA User Manual – 3. Connections
12
RS232C Interface
Ì
DTE/DCE
If the full EIA232 standard is implemented as defined, the equipment at the far end of the connection is named the DTE
device (Data Terminal Equipment, usually a computer or terminal), has a male DB9 connector. Equipment at the near
end of the connection (the telephone line interface) is named the DCE device (Data Circuit-terminating Equipment,
usually a modem), has a female DB9 connector. The cable linking DTE and DCE devices is a parallel straight-through
cable with no cross-overs or self-connects in the connector hoods. If all devices exactly followed this standard, all
cables would be identical, and there would be no chance that an incorrectly wired cable could be used.
Ì
DB9 Female
Promi SD205-OA is a DCE device compatible with RS232 standard, having DB9 female interface.
Pin #
Signal
Direction
Description
1 N/A
2 RxD
Input
Received Data
3 TxD
Output
Transmitted Data
4 N/A
5 N/A
6 Vcc
Input
5V~12V
7 N/A
8 N/A
9 GND
Signal Ground
