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, involve the transitioning from various legacy synchronous protocol stacks (e.g. X.25, HDLC, LAPB, Bisync) to the modern TCP/IP stack.
Hardware
We designed, build and sell the PXSu which provides a synchronous port via a USB interface, enabling reliable data transfer for various applications. The PXSe, a synchronous-to-TCP/IP gateway kit, is no longer available for purchase; however, its functionality can be replicated using the PXSu combined with a small computer.
Our hardware supports a wide range of physical interfaces, including RS-232, RS-422, X.21, EIA-530, and V.35, with bit rates up to 4 Mbps. It also supports multiple data encodings, such as NRZ, NRZI, FM0, FM1, and Manchester, ensuring compatibility with diverse systems.
Software
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.
Solutions
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:
- Gateways for Radar Data (e.g Asterix) in synchronous mode (HDLC or HDLC/LAPB or HDLC.LAPB.X.25).
- Tunneling of Synchronous data over a TCP/IP link.
- Replacement of X.25 networks, using TCP/IP as transport mechanism.
- Accessing of Telephone Switches CDR and management records from TCP/IP networks.
January 1, 2024, marked the final opportunity to purchase our PXSe product. Rest assured, technical support will remain available for the foreseeable future.
[Last updated October 1st, 2025]