If I’m away from home, how do I retrieve my messages?

SOURCE: retrieve messages away from home on a Panasonic KX-FPG381

You have to set a polling number, you WILL need a manual. Use your keypad just enter this number when you phone home

SOURCE: Uniden Answering Machine - retrieving messages

My login didn't get accepted with the above solution.
I want to edit that this solution works for my older 2.4GHz base units (models DCT-748 and DCT-7488) - both are about 3 yrs old.

SOURCE: How do your retrieve messages from home while away from home

Here's the manual:
29869GE2 Digital Answering Machine
You will need to set a security code. When you're away you can call your home phone and enter the code to retrieve your messages. Hope this helps.

SOURCE: Retrieving messages away from home.

Hello,

When you are away, you call your number and waiting for the welcome message (your message). When the machine invites you to leave a message you enter your secret code, the one you entered when you configured the machine. (Usually there is default, but since you don't have a manual there is no point guessing (although 123 may do the trick). Some older phones have a code sticker on the underside of phone.)

When the code is recognized the machine starts giving instructions press (number) to (do something).

Hope it helps.

SOURCE: how do i retrieve telephone messages when away

A remote code must be entered to operate the system remotely. The factory code setting is "111" and you can set your own personal code by following the directions on page 31 of the phone system operating guide.

To check messages from a remote location, dial your number from any touch tone phone, enter your code after the greeting message begins, then follow the voice prompts.

Need the manual? You can download/print it here:

http://service.us.panasonic.com/OPERMANPDF/KXTG1032.pdf