Mitel 5220 IP phone "loses" registration when connected computer reboots?

[autoint]

One of our users with a Mitel 5220 IP phone consistently experiences trouble with her phone if she reboots her connected computer.

wall plate <====> 5220 <====> HP USB-C dock <====> HP laptop

When the user reboots her computer, the phone appears to lose its registration (?) with the 3300 ICP (old platform). If she is on a call, the call is dropped. Blinking squares briefly appear at the far right on the phone display. If she picks up the handset, there is no dial tone. If she presses the Speaker button, a message appears, "please wait." If she waits for a bit, the phone apparently re-registers and she can use her phone. I swapped out her phone for a different 5220, but the problem persists.

Any suggestions?

Thank you!

 

[Valamagules]

What happens If you disconnect the cable between the 5220 phone and the HP Dock?

Clever men learns what Wise men shares!

 

[Mike__K]

I wonder if the docking station is pulling the RJ45 pins to ground on restart, that would cause a brief loss for the phone. What happens if you connect the laptop direct (or to an Ethernet dongle if it has no RJ45 built in) and skip the dock?

 

[autoint]

The laptop has no integrated RJ45 socket/port. I connected a SIIG USB 3.0 to Gigabit Ethernet usb adapter (ASIX AX88179), and patched the laptop directly to the 5220 phone. The connection works normally and I can reboot/shutdown with no disruption to phone/registration. I also tried a different laptop/model that has an integrated RJ45 socket/port. Again, this worked normally, and reboot/shutdown didn't affect the phone. An interesting, though probably not overly helpful observation: the laptop sometimes doesn't recognize the (HP USB-C G4) dock correctly. When this happens, the laptop still charges through the dock, but doesn't recognize peripherals connected to the dock (external keyboard/displays) or the Ethernet/network connection on the dock. In this state, I can reboot/shutdown the laptop with no effect on the phone. A 30-second power button + F5 "reset" (shutdown and disconnect from external power, then use button/key combination) gets the laptop to recognize/detect the dock again, and the phone problem with shutdown/reboot returns. I'm not sure what the power button + F5 reset does exactly. This is a workaround an HP tech provided during a support call. I haven't been able to find any HP documentation on a power button + F5 reset.