A TETRA communications system, comprising: a first TETRA communications device 100, operable to establish a first communications link in an ETSI standard TETRA direct mode or trunked mode with a respective other device or devices; a second TETRA communications device 200, operable to establish a second communications link in an ETSI standard TETRA direct mode or trunked mode with a respective other deuce or devices; a data link 300, which may be an IP network, a fibre optic cable or a serial data cable, connecting the first and second TETRA communications devices to transport TETRA user plane message data and control information bet`veen the first and second TETRA communications devices; and control means for operating the first and second TETRA communications devices to transport said user plane message data and control information, which may be encrypted, between said first and second TETRA communications devices via the data link.
展开▼
