|Updated 8 June 2003||Yaesu Vertex VX-900 Technical|
Yes, there is a way to do field programming. You need to short pins 3 and 7 of the external mic connector, then hold down the lamp and PTT button while powering the radio on. You will see "FIELD" in the display. (The "lamp" button is the bottom button below PTT.) Pins 3 and 7 are the 2nd and 4th pin down on the left side as you are looking into the connector on the side of the radio.
Then using the channel knob, select the function you want to program, and using the top and side Set buttons change the entries. For frequency, use the toggle switch to select MHz, tenths, hundredths and the top/side set buttons to change the applicable item. (The side "set" button is the top button above the PTT, and the top "set" button is the orange button.) After changing an entry, turn the channel knob to another position to "enter" the change. Power the radio off and back on to go back to normal operating mode.
This is an excerpt from The Radio Information Board