Rockwell Automation DAG6.5.8 APPLICATION GUIDE SCADA SYSTEM - Manual (Page 230)

Publication AG-UM008C-EN-P - February 2005
7-4 Configuring Logix Controllers
Dial-up Phone Modems
Dial-up phone line modems support point-to-point full-duplex
communications. Normally, a Logix controller on the initiating or
receiving end of the dial-up connection will be configured for DF1
full-duplex protocol with the control line parameter set for
Full-Duplex Modem. See page 7-7 for details on the operation of the
RS-232 modem control signals when Full-Duplex Modem is selected.
Refer to chapter 11 for further details on using Logix controllers in
dial-up modem applications.
Leased-Line Modems
Leased-line modems are used with dedicated phone lines that are
typically leased from the local phone company. The dedicated lines
may be point-to-point topology supporting full-duplex
communications between two modems or in a point-to-multipoint
topology supporting half-duplex communications between two or
more modems. In the point-to-point topology, configure the Logix
controller for DF1 full-duplex protocol with the control line parameter
set to Full-Duplex Modem. In the point-to-multipoint topology,
configure the Logix controller for DF1 half-duplex master or slave
protocol with the control parameter set to Half-Duplex Modem
without Continuous Carrier. See page 7-7 for details on the operation
of the RS-232 modem control signals when Half-Duplex Modem
without Continuous Carrier is selected.
Radio Modems
Radio modems may be implemented in a point-to-point topology
supporting either half-duplex or full-duplex communications, or in a
point-to-multipoint topology supporting half-duplex communications
between two or more modems. In the point-to-point topology using
full-duplex radio modems, configure the Logix controllers for DF1
full-duplex protocol. In the point-to-multipoint topology using
half-duplex radio modems, configure the Logix controllers for DF1
half-duplex master or slave protocol. If these radio modems require
RTS/CTS handshaking, configure the control line parameter to
Half-Duplex Modem without Continuous Carrier.