Paul Strawbridge, a director of the Liphook-based company, said secure ISDN phones are widely used in the public sector, the military and police forces around the world.
The devices themselves tend to be manufactured by companies dedicated to this activity, i.e. not generic handset makers. In the UK the Brent phone is made by Selenia (formerly part of the Marconi group); in the US they are referred to as Secure Telephone Unit (STU) or Secure Terminal Equipment (STE) phones and are made by a variety of companies.
The secure, encrypted connections such devices enable over traditional circuit-switched TDM networks cannot a priori be replicated over IP, because as a packet-based technology it is asynchronous and non-clocked. ISDN phones require a clear, clock-locked 64k connection that IP can’t deliver, he explained.
Patapsco’s PacketBank system, however, can tunnel ISDN over a packet network such as IP and, as Strawbridge put it, recover the clock to a very high degree across a non-clocked link, making it possible for organizations that have lots of secure ISDN phones already to use them on IP networks.
Strawbridge said Patapsco really has only one competitor in the ISDN-over-IP space, namely Israel’s RAD Group, the difference being that the latter runs ISDN over its TDM-over-IP system to enable only dedicated point-to-point connections, whereas Patapsco can do any-to-any.
Patapsco Communications is in fact the trading name of Patapsco Designs Ltd, which was formerly the UK branch of US company Patapsco Designs Inc. The UK broke away from the US parent in the early nineties, however, and is now a separate entity operating in a different market space. It remains privately held and, according to Strawbridge, derives the bulk of its revenue from the international market. We’re widely used in the Middle and Far East, he went on.
