This section describes some of the hidden abilities of the Nav Plus system. Care should be taken with these menus as they are designed for service personal. You can cause your Nav Plus to not work with incorrect use. Tuner Functions: Tuner Menu One: Press and hold the "Tone" button until it beeps. (about 10 seconds). This will display test parameters for the tuner. The field strength can be used to verify your antennas are working correctly. A setting of about 200 to 250 seems normal for FM, and about 80-100 for AM. Tuner Menu Two: After tuner menu one is displayed, press and hold the "Tone" button again until the next menu is displayed. Communication and Software Functions: Communication Display: Display the Navigation screen. Press and hold the "AS" key and the down arrow at the same time. This menu displays how the Nav Plus system is communicating with the other parts of the car. The functions are described below... Logbook: An optional piece of hardware which allows you to program routes and upload tracks on a personal computer. TV Tuner: If you have the newer "B" version of the tuner, it should show up here. CAN Gateway: The TMC (traffic message channel) box. The TMC doesn't do much in North America. If you have one, it should say OK. Telematics: Not used in North America. This is affected by adaption channel 6. Multi Function Steering Wheel: Not used in North America, at least on A4's. Some of you with A6's and A8's will be able to make this work. (see "programming your car" elsewhere on the site.) Voice Control: An optional module that allows you to speak commands to the Nav Plus unit. Great for dialing the optional phone that nobody has. Dash Panel: Should say OK. The picture has a warning "Switch on term.15!" because I didn't have my ignition turned on when I took this shot. If any of the settings look wrong, check adaption channel 7 to recode your unit correctly. Software Display: With the above communication menu displayed, press the right hand knob This menu displays the software revisions of your Nav Plus. It's useful for checking to see if the firmware can accept a software update. Press the right hand knob one more time. The "Stamp" menu item here is interesting. If you don't have the "Nov 15, 2001" software, you can update your unit. This version adds the 50 meter display, the compass and more. Press the "Flag" key. (note this only works if you entered the above menus from the Navigation screen.) This allows you to see parameters used for the speed sensor (GALA) for the Nav plus. The tyre (sic) circumference is the diameter of your tire in mm. Some common tire sizes... 185/65 R15: 1895 195/65 R15: 1935 205/60 R15: 1910 205/55 R16: 1930 225/45 R17: 1930 225/40 R18: 1943 The "Pulses per Revolution" is set depending if your car is using the Gala signal or the ABS signal. For the Gala signal, the correct number is 8, and for older cars using the ABS the correct number is 45. Software Updates: Updating the firmware: With the unit powered off, press and hold the Navigation button and the flag button. Continue to hold these as you power the unit on. This menu allows you to update the firmware on your Nav Plus. Currently the Nov 15, 2001 firmware is the latest available. See instructions elsewhere on this site on how to update your software. Antenna Control: This is only available if you have the optional TV tuner: Press and hold the "AM" button and the "TONE" button at the same time. This menu allows you to test the television diversity antenna system in your car. You can turn on one antenna at a time to verify each amplifier is working correctly. Other Tricks: There are a few other tricks hiding in the Nav plus, such as holding the display button for 5 seconds taking you to the contrast menu. You can even change the startup screen with your own picture with a bit of work.