Electronic Alarms and Home Security Devices - ADT Safewatch Pro 2000 Code not understood!!

I have an ADT Safewatch Pro 2000. There is a code of 6F on the display panel. It is not an alarm and does not say "check" or does not stop the system arming. The "6" seems to refer to some patio doors (5 total) because when I open them I get the 6F and "not ready" warning.
I don't understand the "F". Every other zone has just a number.
If anyone has any ideas please post. Thanks

It is actually bF, it stands for backup failure. This happens when the cellular backup unit is not working. Do you have an old analog unit that is no longer monitored. If not, you may have had a cellular outage when the cellular tried to test. To clear, disconnect telephone cord at the RJ31X jack, then enter code+5+1 to test. Wait for the keypad to show cd, and clear the message with code+1, code+1.

Thanks for your imput. Yes it is not monitored and probley an older model. Is there any way to switch off this message if there is no monitoring?

I have a ADT Safewatch Pro 2000. I'm getting a bf code error. The alarm is not monitored and has some sort of radio transmitter attached to the system. I think it was installed in 2000. Is there anyway to remove this code permanently? kcxj if you are arround I think you know the answer to this.
Thanks.

Step 1: Power down the system and remove the wires connecting the system to the cell dialer.

Step 2: Since I am guessing that you don't know the installer code; restore AC power and within 50 seconds press * + # simultaneously. It should jump in to program mode.

Press # 20 and it will read back the installer code, 1 digit at a time (most likely it will be 6321).

Press *41*, *42*, *29 0, *94*, then press *99 to exit programming.

This turns off the phone dialer, makes the system stop looking for the cell dialer, keeps ADT from dialing into the panel, and gets you back to normal run mode.

This is a modified Vista 20se. Websearch using the phrase "Vista 20se installer manual".