Converting Synchronous Protocols to TCP/IP

Advanced Relay Corp. has been at the forefront of developing, selling, and continually supporting both software and hardware tailored for synchronous data communications. Most applications, whether developed by us or by our customers, typically require the transitioning from various legacy synchronous protocol stacks (e.g. X.25, HDLC, LAPB, Bisync) to the modern TCP/IP stack.

January 1st of 2024, was the last opportunity to purchase our products.

This website features basic commercial details, complemented by a comprehensive support section dedicated to enhancing the experience for our existing customers. Our commitment to assisting our customers remains steadfast for the foreseeable future.


  • PXSe, a whole synchronous to TCP/IP gateway kit.
  • PXSu, a synchronous port through a USB interface.

Our hardware supports the most common physical interfaces (RS-232, RS-422, X.21, EIA-520, V.35) and bit rates of up to 4 Mbps. Multiple data encodings are also supported (NRZ, NRZI, FM0, FM1, Manchester).


The core of our software is the LayGO® API, which provides all the necessary functions to establish a data exchange with a synchronous channel. This software is part of the LayGO® toolkit that also includes either the PXSu or the PXSe used just as a synchronous card replacement.

The LayGO® API supports multiple protocols including X.25, LAPB, LAPD, HDLC and BSC.

Using the LayGO® API and the PXSe, we developed a series of solutions to ease the communication with legacy synchronous devices e.g.  Radar Systems, Telephone Switches and Defense Systems.


We offer several solutions that encapsulate synchronous data from legacy devices into TCP/IP packets. This allows developers to integrate modern equipment with legacy devices in a very easy way. Among them:

[Last updated May 29th, 2024]