How do i change extension number on a merlin magix 4406d+

Go to the telephone switch
A. Log in
B. Do a change station
C.On the form Put your number in press enter
D.On that form change the primary preference to any button you want it to be.

RJ45 pinout link here:
RJ 45 pinout
Hope this helps.

consult your instr. manual and read if you do not have go www.retrevo.com and download and proceed according.
God bless you

from the main phone

menu
sys program
start
arrow (more optiolabeling
directory
extension
enter extension, then change the name

To program your Personal Speed Dial numbers, make a list of
your telephone numbers/extensions numbered 1 to 24, then:
Press an Intercom button + lift handset + dial #00 + dial # + list number (01 to 24) + dial *21 + the number you want to store + #*00.

To use Personal Speed Dial:
1: Press an Intercon button.
2: Press Feature (if you have programmed a "Feature" button) or #.
3: Dial the two-digit code (01 to 24).

Assuming that you have a Merlin Magix and not an IP Office. You will need to do this on a 4424LD+, not the 4412, though.

Changing time on a Merlin Magix/Legend.

or, if this is a Magix, the 4424ld+

What hunt group? Voicemnail? Regular huntgroups for calls?

If D-channel is dropped, you will get red light.
When B-Channels are in use, you will get amber light.

Try rebooting both systems. Are they both grounded?
Has this been the case from the get go, or just come up?