Features:

--Supports SIP2.0 protocol and can register 2-way SIP accounts.

--Supports free dialing or automatic dialing when off-hook.

--Supports external 30W speaker amplification and integrated call warning light.

--Supports detection of busy tone reception.

--Works with a SIP server to enable group calls, recordings and other functions.

--Support 2 groups of one key-dialing (quick dial function).

Applications:

Cities, ports, factories, tunnels, warehouses, power plants, wind mills, etc.