BT Quartet Diverse 2015 - Manual (Page 66)

Technical information
62
If you do have a compatible
switchboard, it cannot be
guaranteed that the telephone will
operate correctly under all possible
conditions of connection. If you have
any difficulties, contact BT on
154
or the Diverse Helpline on 0345
908070 .
Generally Diverse 2015 can be
connected to any switchboard where
a simple modern telephone can be
used to make and receive calls.
Diverse 2015 is suitable for
connection to switchboards which
return secondary proceed indication.