Uniden SSE27 range form base and volume increase on portable handset

SOURCE: tru9466 base and tru9465-2 handset

Same manual as lethean provided on a similar post but Page 24 if the previously used Base is Unavailable and your phone shows "Deregistration" in the Menu.

Base Unavailable (Handset Only)
To clear the base registration data in the handset, please follow these steps:
Press and hold [] and [#] for more than 5 seconds. Select the BASE UNAVAILABLE submenu.
BASE UNAVAILABLE appears. Move the cursor to select YES, and then press the OK soft key.
ARE YOU SURE? appears. Move the cursor to select YES. Press the OK soft key.

SOURCE: How to remove Uniden handset from base

The brillian people at Uniden don't feel it necessary to provide this type information in their manuals. You have to trial and error to find it, but what can you do. All you have to do to reset the base unit itself is to unplug the power, then while holding down the delete key, plug it back in. Hold the delete button down until you hear a beep, which indicates it has reset. Now you can readd handsets and they will start at 1.

SOURCE: Reset base unit of Uniden TRU9485

Uniden TRU9485 (This didn’t work for me but this was the first instruction from Uniden Tech Support)

TO RESET THE BASE UNIT:
Unplug the base unit AC adapter.
Hold down for 15 seconds the DND, * and “menu” soft key (the middle silver soft key under the LCD) while plugging the base unit AC adapter back in.
All the settings should be reset.

Uniden TRU9485 (Worked for me)
ALTERNATE WAY TO RESET THE BASE UNIT:

Unplug the base unit AC adapter.
Hold down for 15 seconds the DELETE KEY (zero with a line through it) while plugging base unit AC adapter back in.
All the settings should be reset.

SOURCE: ADDING HANDSET SAYS OUT OF RANGE

A search of Uniden support only said to call 1-800-297-1023 with handset registration issues. The rep picked up quickly and walked me through the reset procedure. Here it is step-by-step:

1. Remove battery
2. Hold down the * and # buttons and reinsert battery. You should hear a long beep. If not retry. (This is a bit awkward but hold the handset upside down and it's workable)
3. Screen will be blank. Immediately press the right soft menu button.
4. Screen will report that EEPROM is clearing and then state EEPROM Clear Ok
5. Remove battery (yes again)
6. Reinsert battery (this time there's no need to hold down any buttons)
7. Handset will reboot with Welcome screen and then state that phone must be registered (this is the status a handset should be in from the factory)
8. Place handset on base and it will register as normal

SOURCE: how do you adjust volume on base ringer on uniden dxa15588-2

Setting the Main Base Ringer Volume
The main base has three ringer volume settings: high, low, and off. You can change
the ringer volume while in standby mode or while an incoming call is ringing.
1) Press the ringer key.
You hear the ringer at the current volume level
([ ] High, [ ] Low, [ ] off) (if you set the
main base ringer volume to off, “Ringer off” is
announced) and it is displayed on the main base.
2) Press the ringer key repeatedly until the desired ringer
option appears.
3) The system displays the new ringer volume.