International Packet Switched Service

The International Packet Switched Service (IPSS) was created in 1978 by a collaboration between the United Kingdom's General Post Office, Western Union International and the United States' Tymnet.

This network grew from Europe and the United States to cover Canada, Hong Kong and Australia by 1981, and by the 1990s it provided a worldwide networking infrastructure.

Companies and individual users could connect in to the network, via a PSS (Packet Switch Stream) modem, or an X.25 PAD (Packet Assembler/Disassembler), and a dedicated PSS line, and use it to connect to a variety of online databases and mainframe systems. There was a choice of about three different speeds of PSS lines, although a faster line was more costly to rent.

By 1984 British Telecomm had joined the PSS global network and was providing IPSS services to customers. Companies including Dynatech, were providers of Interconnectivity and infrastructure devices including line drivers, modems, self configuring modems, 4port, 8port and 16port PADs, and Switches. These were physical boxes delivering full impmentation of x.25, x.28, x.29, x3 protocols with physical connectivity conforming to RS232 synchronous connectivity specification.

In 1988 the IPSS directory listed approximately 800 global sites available for connection via X.25