MD-N33 Serial RS-232 to PSTN Adapter (Modem)


The MD-N33 is a data communication modem for data transfer over the worldwide PSTN networks. This sturdy and efficient modem links RS-232 based serial communication devices over dial-up telephone lines for remote applications. It can be used to connect the phone line on the PC side or remote unit connection. The intelligent DAA technology detects line status.

The MD-N33 features auto-dial, redial, and auto-answer, as well as non-volatile memory to store user profiles. The unit also includes line protection circuitry.

The MD-N33 is a V.34/33.6K modem and complies with worldwide telecom requirements. The modem is AT Command set compatible and can be configured from any PC‑based communication program.

It is crafted from the finest materials and to the highest manufacturing standards under Rosslare’s ISO 9001:2008 Certified Quality standards.

  • Configurable via a PC connection to connect either a phone to a PC or to a remote unit
  • V.34/33.6K
  • AT command compatibility
  • 60-character command line buffering
  • Auto-dial, redial, and auto-answer
  • Pulse or tone dial
  • Connectors:
  • Front: RJ-11 jack and power jack
  • Rear: RS-232 jack


  • Remote hang-up detection
  • Digital PBX detection and protection
  • Buzzer for call progress monitoring
  • Two LEDs indicate telephone line status and power supply
  • Intelligent DAA technology detects line status
  • Industry-standard error correction and data compression
  • DTMF detection and distinctive ring
  • Non-volatile memory to store user profiles
  • Line protection circuitry included