Enables up to four synchronized co-located base stations to be used together for a total of 44 COMMUNICATORs with up to 16 in hands-free, full-duplex mode. Make DX210 compatible with existing 2-wire partyline or 4-wire matrix systems provided by Clear-Com or RTS, allows all wireless users on the same base station to talk with each other, isolated from either two- or four-wire intercom channel. ISO function can be restricted to specific users. Provides the deepest hybrid balancing in the industry and is flat across the entire speech bandwidth. The DX210 is equipped with an auto “nulling circuit” to easily null 2-wire connections and eliminate echo automatically.