NXDN is an open standard protocol developed jointly by Kenwood and Icom. NEXEDGE is the Kenwood branding version and IDAS is the icon branding version. The radios can communicate across NXDN and IDAS as the protocol is the same.
NXDN uses Frequency-Division, Multiple-Access (FDMA) technology in which different communication streams are separated by frequency and run simultaneously.
NXDN is a digital mode with an original target user base for business and industry. Public safety has also adopted NXDN in some areas. The channels can be 12.5 kHz or 6.25 kHz. The mode can transmit voice or data and is not compatible with other digital modes such as P-25, DMR, TETRA, D-Star, or System Fusion. However, the equipment can support mixed-mode analog FM use.
RAN (Random Access Number) is similar to a CTCSS encode for analog systems. It unlocks the squelch on the repeater while you transmit to permit access to the repeater. There are 63 codes.
The NXDN protocol does include encryption. Refer to the rules of the Amateur Radio Service for the legality of using such technology. In the US, if the intent is to obscure communications, it is expressly prohibited.
Repeaters with NXDN capability can be listed on RepeaterBook. Repeaterbook displays on the repeater's details page the RAN Code, bandwidth, and associated network, if known.