how can Opmanager alerts be sent to a GSM modem without serial port?

how can Opmanager alerts be sent to a GSM modem without serial port?

Hi there,
      It's a kind of Apollo13 rocket science we've seen in Hollywood. 

      I want to connect a server with Opmanager Build 8812 to an existing SMS alarm system, named T, with GSM modem functionality but without COM port. T accepts only digital voltage input.

      Is there any work-around solution?

B.

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