Hardware Manual for the PCD3 Series│Document 26/789; Version E 5│31.01.2005
Saia-Burgess
Controls Ltd.
Defi nitions of serial interfaces
Appendix
9-2
9
9.2
Definitions of serial interfaces
9.2.1 RS 232
Designation of signal lines:
Data lines
TXD Transmit data
[Sendedaten]
RXD Receive data
[Empfangsdaten]
Signal and message
lines
RTS Request to send
[Sendeteil einschalten]
CTS Clear to send
[Sendebereitschaft]
DTR Data terminal ready
[Terminal bereit]
DSR Data set ready
[Betriebsbereitschaft]
RI
Ring indicator
[Kommender Ruf]
DCD Data carrier detect
[Partner bereit]
Signals to RS 232
Signal type
Logical state
Required value
Nominal value
Data signal
0 (space)
1(mark)
+3 V to +15 V
-15 V to -3 V
+7 V
-7 V
Control/
message signal
0 (off)
1 (on)
-15 V to -3 V
+3 V to +15 V
-7 V
+7 V
The idle state
of the data signals = “mark”
of the control and message signals = “off”
