ITL-6DE-1P (DT700) not defaulting

[TeleBug27]

I have an NEC ITL-6DE-1P (DT700) on a SV8100 that will not default or register on the system.

Even after factory defaulting it boots and displays extension 1100, which is an extension not registered on the SV8100.

The phone has previously been used, the previous system or settings unknown.

 

[belevedere]

It seems as though the factory default did not run. Try it again.
If the phone will not do a factory default, then I would try loading in updated firmware or reloading in the existing firmware. If all of that fails, then replace it.