Westermo TD-22 - Manual (Page 49)

50 6177-2203
RS232 Signals
TD
Transmitted Data. Data going from DTE to DCE.
RD
Received Data. The Data going from DCE to DTE.
RTS
Request to Send. Hardware handshake generated by the DTE to determine if the DCE is ready to
receive data. Expected response is from the CTS line.
CTS
Clear To Send. Hardware handshake by DCE in response to an RTS signal.
DSR
Data Set Ready. A signal from the DCE used to say that is powered and usable.
DTR
Data Terminal Ready. A signal from the DTE showing it is powered and usable.
DCD
Data Carrier Detect. A signal from the DCE showing that a carrier is present and a line is ready for
data transmission.
Simplex
Unidirectional communication.
Start bit
Marks the start of a transmission. In asynchronous transmission each character is preceded by a start
bit.
Stop bit
One or more stop bits mean that the character has been transmitted. Systems that use two stop bits
can cause problems with some modems as the modem will remove the second stop bit to gain better
data throughput and then not put it back.