Installing and securing VoIP with Linux
We have been using Linux for years as firewalls and we knew there had to be a low cost open source solution to fulfill the requirements, and that's when we found 'Asterisk'. It's a full blown Linux based PBX system meeting all the requirements of voice mail, conference calling, caller ID, call parking, music on hold, PBX to PBX dialing and much more. Asterisk was created and founded by Mark Spencer, who later started Digium. Digium is now the primary sponsor and developer, and they also offer software support as well as compatible hardware for use with Asterisk. We looked on Digium's website ( http://www.digium.com ) for the necessary hardware and found for a mere $500 their T100P product which would replace the DSU/CSUs (this card plugs directly into the "smartjack") and the telco routing equipment. This card is simply amazing. It's no bigger than a 1/2 height PCI network card with a RJ45 port to connect to a DS1/T1 circuit. It can then be used to split the DS1/T1 voice and data channels.
By Bruce Wink and Champ Clark at softwink.com
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