InLink-TC is a HART protocol modem module that modulates logic level 1200 BAUD serial data onto a HART loop, and demodulates received HART data providing a 1200 BAUD serial bit stream. InLink-TC interfaces to standard 3.3V to 5V logic and only requires 3 control lines; transmit, receive, and request-to-send (RTS). InLink-TC is a complete HART protocol modem - adding only RS232 transceivers and a power supply makes an RS-232 to HART interface. Loop transformer isolation eliminates loop connection polarity and grounding  issues and an internal 3V regulator and logic level shifters ensure consistent operation over a wide operating voltage range. The InLink-TC small package size further simplifies integration into your design.

InLink-TC Data Sheet (PDF)
For a non-isolated capacitor-coupled HART protocol modem see the InLink-CC
For transformer isolation and modbus accumulator see the InLink-HM

 InLink-TC Block Diagram 


InLink-TC Typical Application

InLink-TC Typical Application, RS-232 to HART Protocol Interface
using the InLink-TC modem module.


  • Complies with Hart protocol physical layer

  • Transformer isolation and capacitor coupling eliminate grounding effects and polarity issues

  • Complete modem module - reduces time-to-market

  • Small footprint - simplifies design integration

  • Rugged encapsulated package with gold-plated pins for increased reliability

  • Through-hole or socket mounting

  • Wide supply range, 3.0V to 5.2V

  • Industrial temperature range, -40°C to +85°C

  • Transmit signal wave-shaping - sinusoidal with lowest harmonic distortion

  • Receive band-pass filter and digital processing for reliability in noisy conditions

  • CMOS compatible control lines - wide operating voltage range

  • Low power

  • Evaluation board available