User manual

Publication 1747-UM011F-EN-P - May 2007
212 RS-232 Communication Interface
ASCII Communication
ASCII protocol lets you connect the SLC 5/03, SLC 5/04, and SLC 5/05
processors to serial printers, personal computers, and other third-party
devices. ASCII protocol lets your ladder program manage ASCII data.
DF1 Communication
Protocol Modems Overview
You can connect the SLC 5/03, SLC 5/04, and SLC 5/05 processors to
several types of modems. In all cases, the processors act as Data
Terminal Equipment (DTE). DTE send and/or receive data on a
network. Modem or line drivers act as Data Communication
Equipment (DCE), which provide the signal conversion and coding
required for communication between DTE and data circuits. Other
DCE include phone-line modems and specialized modems, such as
radio and satellite-link modems.
In addition to Common Return (COM), Receive Data (RXD), and
Transmit Data (TXD), the following active modem-control lines are
provided on the SLC 5/03, SLC 5/04, and SLC 5/05 processors.
RTS (Request to Send) - this output signal indicates to the modem or
other DCE that the DTE wants to transmit.
CTS (Clear to Send) - this input signal from the modem indicates the
modem is ready to receive the transmission by the DTE for forwarding
over a link.
DSR (Data Set Ready) - this input signal indicates the DCE device is
ready for operation. Loss of this signal causes a modem-lost condition
in the processor.
DTR (Data Terminal Ready) - this output signal from the DTE indicates
that it is ready for operation. You can also use this signal with the
processor to initiate DTR dialing in dial-up modems that support such
a feature.
DCD (Data Carrier Detect) - this is an input signal from the DCE that
indicates a carrier signal is being received and that presumably data is
to be received for forwarding to the DTE connected.
Modular Controller with
SLC 5/03 Processor
RS-232 Channel 0
1747-CP3 Cable