Since firmware version 126.96.36.199, we inhibit (by default) the option to insert letters in the dial screen.
In order to restore this possibility you can turn off the setting block_url_dialing.
You can perform this in three ways:
- Through the Web User Interface → Advanced → Behavior (Tab) - Phone Behavior (Section): Block URL Dialing
- Via HTTP Request
- Via provisioning
Once you have turned Block url dialing to off, you can enter letters again in the dial screen:
Screenshots from D385 - FW: 10.1.64.14
You must press the "Edit Mode" button (leftmost button) to change the setting from "123" to "abc".