Mitel SX-2000, SX-200 User Manual - ManualMachine.com Mitel Networks 5448 Programmable Key Module: The Mitel Networks 5448 Programmable Key Module provides 48 additional feature keys for a 5020 IP Phone. They can be programmed as Feature keys, Speed Call keys, Direct Station Select keys, or as Line Appearance keys. Each key has a Line Status Indicator that works the same way as those on the ...