The NXDN Forum has adopted a second trunking protocol. The designators for these two trunking protocols have been established as follows:

Type-C NXDN trunking: This is the original NXDN trunking protocol based on dedicated control channel logic architecture.

Type-D NXDN trunking: This is the newly adopted NXDN trunking protocol, and is based on distributed logic architecture. (No dedicated control channel required)

Both protocols will be managed by the NXDN Forum to ensure interoperability and maintenance of each protocol going forward. There will be interoperability between vendors of the trunking protocol they adopt. Both protocols meet the FCC narrowbanding mandate, and thus system operators and end
users who adopt NXDN trunking will be in a position to be ready for the 2013 narrowbanding deadline.