Mitel Superset

[1] The line began in 1983, with the Superset 4, Mitel's best-selling device to date.

[2] The Superset 4DN was one of the first Digital Telephones[3] made by Mitel and was announced in October 1986.

Source:[4] The 400 range consisted of a 401+,410,420 and 430[5] See The telephones connected back to the Mitel exchange digitally using 1 pair of cables.

A Mitel MT8971BP IC was used in this range of handsets to communicate with a port on the DNIC card in a SX 50, SX 200 or SX 2000 Mitel switch All in this range apart from the 401+ were loud speaking telephones, allowing the user to converse fully hands free.

The 4000 series supersedes the 400 series and consists of the 4001,4015,4125 and 4150[6] The Superset 4001 has no LCD display and has similar functionality to the 401+ The 4001 has 4 main Ic's - A Motorola SC427602FN With 93C46B,MT9196AP,MT9171AP and a MC33362 PSU IC