Rockwell-automation 1770, D17706.5.16 Ref Mnl DF1 Protocol Command Bedienungsanleitung PDF herunterladen (Seite 33)

2–4 Understanding DF1 Protocol

Publication

17706.5.16 - October 1996

Fullduplex Protocol

Use full-duplex protocol:

• over a point-to-point link that allows two-way simultaneous

transmission

• over a multidrop link where interface modules are able to

arbitrate transmission on the link

• for high performance applications where it is necessary to get the

highest possible throughput from the available medium

If you connect an interface module to another Allen-Bradley

communication interface module, the modules automatically handle

the link arbitration. (For a list of modules that automatically handle

link arbitration, refer to page 4–1.)

Full-duplex dial-up modems

Full-duplex dial-up modems can be used as long as a carrier is

detected before the carrier timeout (about 10 seconds). If a carrier is

not sensed before the timeout, the module drops DTR to trigger the

modem to hang up the phone. A carrier must be sensed at least

every 10 seconds to maintain the connection.

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Rockwell-automation 1770, D17706.5.16 Ref Mnl DF1 Protocol Command Bedienungsanleitung Seite 33