For the Aastra 5370/5370ip and Aastra 5380/5380ip there are two types of expansion modules available.
Expansion module Aastra M530
The Aastra M530 with designation labels includes 20 freely configurable keys with two memory places each.
Expansion module Aastra M535
The Aastra M530 with backlit display includes 15 freely configurable keys. The keys can be programmed on three levels.
For wall mounted terminals, the extension is limited to only one single expansion keypad.