Niobrara QUCM-OE Installation And Programming Manual
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Contents
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QUCM Modbus ASCII Modem Application Manual 3 Operation 213OperationA web browser is used to configure the QUCM. The serial ports must be configuredto set the default modem dialing strings, configuration strings, baud rate, etc. Eachremote slave must also be entered into the QUCM’s look-up table and associated witha particular Modbus/TCP destination index. Each entry consists of the destination in-dex, QUCM serial port, serial protocol to use, remote slave address, the remote tele-phone number, and a text name.QUCM OperationModbus TCP messages arrive at the QUCM during normal operation. The QUCM ex-amines the destination index for the message and if it matches an entry in its setup thefollowing happens:• The QUCM examines the QUCM port number to decide which serial port to use.• The QUCM looks at CTS on the proper port to see if the modem has carrier. (CTSon the QUCM is connected to DCD on the modem with the MM12 cable.) If themodem has carrier, then the QUCM looks at the phone number of the current con-nection to see if it matches the phone number of the target slave. If the numbermatches then the QUCM proceeds to the next step. If the phone numbers do notmatch then the QUCM hangs up the modem by dropping RTS (DSR to the mo-dem) The QUCM should then dial the remote system and wait for carrier..• After the QUCM has carrier on the modem, it translates the message fromModbus/TCP to Modbus ASCII or optionally Modbus RTU or PNIM. The slaveaddress of the Modbus or PNIM message is inserted from the entry in the look-uptable.• The QUCM then waits for the reply. If the reply happens before the timeout thenthe QUCM will translate the Modbus ASCII (RTU or PNIM) reply toModbus/TCP, insert the appropriate destination index, and send the reply back tothe Client. If a timeout occurs then the QUCM will generate an exception x0Breply. |
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