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V130 - Communicating with Land Line Modem

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I need to set up communication between a V130-33-R34 controller and a Zoom land-line modem.  I will be using an RJ11 com port on the PLC, set to RS232.  The modem, unfortunately, is an older-style, and has a D-SUB 25-pin com port.  I will need to build a cable to connect between the two devices. 


I found a D-SUB 25 RS232 pin-out arrangement online.  Data communications is new to me, so I have a pretty basic question: Do I simply need to match the 6 signals on the PLC RJ11 port to the corresponding pins on the modem's cable?  For example, does pin # 1 on the PLC (DTR Signal) get connected with pin #20 on the D-SUB, which, according the pin-out I found online, is also DTR?  Following this logic, the two 0V reference pins on the PLC would be connected to the two GND pins on the modem, TXD to TXD, etc.


Is this correct? 

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The RS232 signal is only sent over 4 of the 6 pins on an RJ11 connector. The pinout for our controllers is detailed in the V130-33-R34 installation guide available on our Technical Library.




The pins will not match exactly. You will want to connect the outgoing pins from the RJ11 port, to the incoming pins on the modem/D-sub cable (Tx to Rx, Rx to Tx). When using RS232 you will also generally not need the DTR and DSR pins. Only 3 of the 6 pins on the RJ11 cable are required to make a connection:

  • Pin 3; From the PLC (Tx) should connect to the Rx on the modem/cable
  • Pin 4; From the PLC (Rx) should connect to the Tx on the modem/cable
  • Pin 2 or 5; From the PLC (0V)should connect to a 0V reference on the modem/cable. Only one connection is required.
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Hello, I have a problem with my new Cinterion TC65 GSM modem-14D, I am unable to initialize it with my PC, I use visiologic OPLC IDE 9.4.0 Build Version 0.
it still Gives me the same error code 284 (modem operation failed modem not connected).
I need your help, thank you.

Best Regards,


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