For some time, Cisco was interested in the compatibility of its VoIP telephony related products with other VoIP vendors, very specifically, to bring their handsets compatible with open-source PBX systems, and more specifically to Asterisk and manufacturers developing their products especially oriented to this system, Digium.
But this is not the only vendor, 3Com has been talking with Digium, Asterisk hardware manufacturer, to use appliances such as communications solution itself.
This statement of intent, rumor mill at the moment, Cisco clashes with the launch of the new range of IP telephony terminals 6900 Series.
This range of terminals using the communication protocol SCCP, Cisco proprietary protocol. Do not use, nor has any support for SIP protocol, mainly used by other manufacturers, in particular communication systems based on Asterisk.
As we know Cisco, Linksys in its range, has terminals compatible with other phone systems.