Amateur Radio Networks
A repeater is a special node which redistributes incoming radio signals on a different frequency or in a different frequency band.
Repeaters can be connected to different Radio Amateur Networks using internet technology (e.g. TCP/IP protocol) and radio signals will be forwarded via internet to other nodes worldwide.
In the moment there are 4 main systems (D-Star, Mototrbo, Hytera and System Fusion). Read more about the Comparison of Amateur Radio Digital Voice Systems.
Some examples of networks are:
ECHOLINK (IP-based network with radio links)
IRLP - Internet Radio Linking Project
IRLP - OEVSV Page
W3WAN - WAN Repeater System
The DMR-MARC Worldwide Network
DMR Digitalfunk (german)
Guide to DMR (.pdf)
DMR - Advanced Protocols
DMR-Brücken zwischen MOT und HYT werden erweitert
(DMR-Bridges between MOT and HYT will be extended...)
A lot about D-Star
ICOM Radio Club
(Who is online...)
C4FM Fusion (YAESU)
Packet Radio Network:
APRS (Automatic Packet Reporting System)
AMPRNet™ — TCP/IP Networking for Amateur Radio