When we were trying to register eSpace7910 phone with U1910 the following error was diaplayed (request time out) and was not able to connect with U1910 .
After that we connected eSpace7910 directly with the LAN port of U1910 still the issue was same.
Then After upgrading the Phone to latest version V100R001C01SPC700 the issue was resolved.
So there is incompability issue between the Phone version & PBX version.
The screen of eSpace7910 with V100R001C01SPC300 software version was every time showing request time out and was not able to connect. Phone was able to ping from the U1910.
First the phone was connected via switch. Then I bypassed the switch & connected directly with the PBX still the issue was same.
I tried with 3rd party soft phone it was working fine.
To check Software compability of SIP Phone with the U1910.
There should be no such dependency of SIP phone on the compability with the U1910 IP PBX.