ISDN Protocol Consulting
Design Pattern Solutions has experience and expertise in the configuration, setup, and extension of open source ISDN libraries, as illustrated in the contributions to open source Asterisk and LibPRI for the addition of PRI SERVICE message support for the '4ESS','5ESS', and 'National' switchtypes enabling users to enable and/or disable PRI channels and/or spans via the Asterisk command-line interface (CLI). Design Pattern Solutions expertise includes, but is not limited to, Dialogic, Digium, and Sangoma products.
Design Pattern Solutions has extended Asterisk and LibPRI for private use as well, for example the addition of Multi-Level Precedence and Preemption (MLPP) functionality to Asterisk 1.8 (not available in open source) and LibPRI which was certified by the Department of Defense. Support for the addition of Information Elements for ATIS 1000619_1992 and 1000619.a.1994 was added as well as the ability to generate proper DISCONNECT cause codes, the proper use of caller precedence and call pre-emption including service domain and network identification.