Aastra Telecom MBU 400 41-001286-00 - Manual (Page 64)

I cannot make Internet calls, but it
worked yesterday.
The MBU is not logged in at the
Internet Telephony Service Provider.
Check that all cables are connected
properly, and check that power is turned
on, and then reset the MBU.
The router is turned off. Turn on the router.
The SIP server is down. Contact your Internet Telephony Service
Provider.
The Internet connection is down. Contact your broadband provider.
How do I determine the software
version of my Handset?
I need to know the software version
currently installed on my MBU 400.
a) Press Volume-Up button on the left
side of the registered 420d handset to
display the system status.
b) Scroll down to see the Version SW:
xx.xx field.
Issue (Continued) Causes (Continued) Solution (Continued)