Answering machine is scrambled

you should definatley try using an inline phone jack filter to seperate the communication waveleighnths

Digital answer phones record the message on a memory chipset in the same way old tape machines did using a magnetic support. Quality can only be improved by the technology itself, problem is with your specific machine.
If you have a broadband filter try replacing it.
Test the machine on a different phone socket and see if it makes any difference.
Check on your answering machine settings, you should find an option to control volume.

Here is the manual for your phone. You can download the manual and the instructions for setting up your answering machine are on page 43:

http://www.uniden.com/pdf/DECT1580-3om.pdf

Setting Up the Answering System
You can set up your answering system's features from the handset. Only one handset at a time can access the answering system menus.

Note: If you have multiple bases, select the base with answering system you want to access (see page 15).

Recording a Personal Greeting
Your answering system comes with a pre-recorded outgoing message or greeting that plays when you receive a call: "Hello, no one is available to take your call. Please leave a message after the tone." You can record your own personal outgoing greeting. Your recorded greeting must be between two seconds and thirty seconds long.

Press /mute. The system announces the number of new and old messages, then starts to play the messages unless it has no messages.

Press 5 to stop the announcements or message playback. You will hear intermittent beeps indicating that the system is in the command waiting mode.

Press 8 to start the recording. The system announces, "Record greeting." Begin recording after the announcement.

When you finish recording, press 8 again or press 5. You will hear a confirmation tone, and your recorded greeting plays back for you.

Selecting a Greeting

Once you have recorded a personal greeting, the phone automatically switches to your personal greeting. You can
also switch back and forth between the pre-recorded greeting and your own greeting at any time.

Press /mute. The system announces the number of new and old messages, then starts to play the messages unless it has no messages.

Press 5 to stop the announcements or message playback. You will hear intermittent beeps indicating that the system is in the command waiting mode.

Press 6. The system plays the current greeting.

It may be similar to the problem I had on wireless home phone with answering machine not taking messages when had the answering machine set to 12 rings before answering. Found the sim card (my wireless system) auto response would answer first. Fixed it by reducing time to 6 rings and answering machine now comes on first.

I have a Bell Phones answering machine model: AN-200SA. It is not recording the messages. We do hear the caller leaving the message. Need to fix urgently. Please can someone kindly assist me!

If the telephone line itself is static-free, connect a normal telephone to the same jack that the answering machine uses. If all calls are static-free, you've cleared the wiring and the telephone service provider. Next, plug the telephone into the jack on the back of the answering machine. If all calls are clean, but messages are still loaded with static, then we may be talking about a bad answering machine. If you have DSL service, make sure that there is a filter installed between the wall jack and the cord that goes to the answering machine.

I have model no. 1188 bellsouth digital answering machine. If you have to leave a message, the message I recorded is no longer there, there is a generic message saying please record your message. How do I go back and record my voice with my message. I cannot find my original manual.

do you have dsl

You have the answering machine set to announce only.

Press the menu button repeatedly until you hear the phone say "set announce only" Press the change button twice The first time tells you the current setting which is "on" the second time turns it off.

Remotely Operating Your Answering Machine

Call your telephone number and wait for the answering machine to answer. If the answering machine is off, it will answer after about 10 rings and series of beeping sounds.
During the greeting message (or a series of beeps when the answering machine is off), press [0] and enter your PIN code within 2 seconds (see "Setting a Security Code or Personal Identification Number (PIN)" on page 54).
The answering machine announces the current time and the number of messages stored in memory. You hear "To play incoming messages, press zero-two. For help, press one-zero." You will hear a beep.
Enter a remote command within 15 seconds, each command there after must be entered within 2 seconds.