Visitation Control System complete with 350-250 15VDC 4A power supply; Insulated screw terminals for 32 units (16 pair); Insulated screw terminals for adding Recording capability to all pairs of devices added to system; Audio balancing components; all mounted on 19’ by 10.5” mounting board for rack or wall mounting; mounting hardware included; completely pre-wired. Requires AC power. Telephone devices are sold separately. Wire/Cable between system and devices not provided. 22-26 gauge Telco wire recommended. This system provides direct one to one talk path for up to 16 pair of devices or 32 total devices, with provisions for easily adding Recording capability.