(edfa-amplifier-settings)=

# Amplifier settings

## Operating mode: ACC recommended

Use **manual pump current control (ACC)** for precision time or frequency transfer.
The AGC feedback loop adds noise that can slightly affect the phase and amplitude of a highly precise signal.
If power levels along the path do not fluctuate often, set the pump current manually and correct large changes from your management system.

## Setting the pump current

Start the CLI with `sysrepo-cli`.

Recommended initial values:

| Module | Initial pump current |
| -- | -- |
| C-band | 62 mA |
| L-band (1572 nm) | 72 mA |

```
set czechlight-bidi-amp:c-band/pump-manual-current 62
set czechlight-bidi-amp:narrow-1572/pump-manual-current 72
commit
copy running startup
```

`commit` applies the change immediately but does not store it.
`copy running startup` saves it to flash so it is loaded at boot.

Then fine-tune the current while watching the power levels on the ports ({ref}`edfa-reading-values`).
The target is a gain of about **23 dB (C-band)** and **22 dB (L-band)**, which means the difference between the input at one side (for example WEST) and the output at the other (EAST) is close to those values.

(edfa-reading-values)=

## Reading the values

```
get czechlight-bidi-amp:*
```

The output lists these nodes for each module (`c-band` and `narrow-1572`):

| Node | Meaning |
| -- | -- |
| `pump/manual-current` | Current you set (mA) |
| `pump/measured-current` | Actual pump current (mA); should be close to the set value when the pump is on |
| `east-to-west/input-power`, `output-power` | Power in the east-to-west direction (dBm) |
| `west-to-east/input-power`, `output-power` | Power in the west-to-east direction (dBm) |

**What to expect on a correctly set link:**

- Input power within the specified range (C-band: −30 to −10 dBm; L-band: −30 to −12 dBm).
- Output minus input about 23 dB (C-band) or 22 dB (L-band).
- Measured pump current close to the manual setting.

If the measured current is 0 or the powers are far outside these ranges (for example inputs near −50 dBm), check that the pump is enabled and that the fibers are connected and clean.

## Switching the pump off

```
set czechlight-bidi-amp:c-band/pump/disabled
commit
```