NEC NEC-1091015 Single Handset 4-Line Landline Telephone NEC DSX 40 Kit with 3 telephones - Initially Configured for 4 CO's x 8 Stations x 2 Analog Ports - Contains (1) 1090001 DSX 40 KSU and (3) 1090020 DSX 22 button display phones. DSX-40 is a compact, wall-mountable, self-contained cabinet. In its off-the-shelf basic configuration, DSX-40 supports 4 CO (outside) lines with Caller ID, 8 DSX digital keyset extensions, and 2 analog (single line) extensions with power failure One audio output for External Paging (1/8 mono mini jack) Two audio inputs for Background Music and Music on Hold (1/8 mono mini jacks) Ethernet and USB ports for local and remote PC Programming