Let’s be clear: This isn't for everyday channel changing. The service menu allows you to fine-tune the hardware. Common reasons to enter it include:

The most common reason to use the service menu is to correct frequency drift or align the radio to a frequency counter.

: To modify a value, hold the PTT while rotating the Channel Selector. Saving : Turn the radio off to save your changes.

Accessing the service menu of the AnyTone AT-5555N II allows for fine-tuning of frequency alignment and carrier settings that are not available in the standard user menu. How to Access the Service Menu

| Parameter | Function | Default Value | What it controls | | :--- | :--- | :--- | :--- | | | VCO Lock Voltage | 2.5 – 4.0V | Do not adjust unless VCO unlocks. | | P-02 | PLL Reference Freq | 0 | Fine frequency calibration (TX/RX offset). | | P-03 | AM Carrier Level | 15 – 25 | Adjusts dead-key carrier for AM mode. | | P-04 | AM Modulation Limit | 90 – 95 | Max percentage of AM modulation. | | P-05 | SSB ALC Max | 80 – 95 | Prevents splatter on sideband. | | P-06 | FM Deviation | 20 – 30 | Sets narrow/wide FM shift. | | P-07 | High Power Scale | 100 – 120 | Digital power amp gain (MOSFET drive). | | P-08 | Low Power Scale | 20 – 40 | Minimum power output floor. | | P-09 | S-Meter Zero | 0 | Calibrates S9 signal reading. | | P-10 | Squelch Threshold | 5 – 15 | Minimum open point for SQL knob. |

: Turn the power on while holding those buttons. Within two seconds (while the LCD segments are displayed), release them and quickly press the following six buttons in order: [DW] , [RB] , [NB] , [SCAN] , [MEM] , and [EMG] .

Depending on your specific firmware revision, utilize one of the following methods.