Substation interface unit designed for use with TOA’s packet intercom system (IP-network), that employs packet audio technology. Substation can be connected using 2 sets of twisted pair cables. The number of LAN connected N-8000 system components such as N-8400RS and IP intercom exchanges, 192 maximum in total. Connecting unit to the LAN permits substation to receive paging calls and make calls to both the master station connected to IP intercom exchange and the IP master station. It can be mounted in an EIA equipment rack (1U) with use of an accessory rack mounting bracket or installed on wall using an optional wall mounting bracket.