Modem FRITZ!Box

AVM FRITZ!Box (Cable)

Overview

The AVM FRITZ!Box is a popular cable modem/gateway in Germany and other European markets. DOCSight supports all FRITZ!Box Cable models via the fritzbox driver.

Property	Value
Driver Key	fritzbox
Auth Method	SID-based session
DOCSIS Version	3.0 + 3.1
Default IP	192.168.178.1
Channels	SC-QAM + OFDM (downstream), ATDMA + OFDMA (upstream)

Setup

1. Set Modem Type to AVM FRITZ!Box in DOCSight settings
2. Enter the FRITZ!Box admin password
3. Default modem IP: 192.168.178.1

The driver uses the FRITZ!Box SID-based session authentication and fetches DOCSIS data via the built-in status APIs.

Known Observations

DOCSIS 3.1 Upstream Power +6 dB Offset

The FRITZ!Box displays DOCSIS 3.1 (OFDMA) upstream power levels approximately 6 dB lower than the actual transmitted power.

Impact: Without correction, the dashboard would show OFDMA upstream power around 35-41 dBmV when the actual value is 41-47 dBmV. This would trigger false warnings about low upstream power.

DOCSight handling: The fritzbox driver automatically applies a +6.0 dB correction to all DOCSIS 3.1 upstream channels. This compensation is applied during data collection so that the VFKD thresholds work correctly.

How to verify: Compare DOCSight's upstream power reading for OFDMA channels with the raw value shown in the FRITZ!Box web interface. DOCSight should show approximately 6 dB higher.

MSE vs SNR

The FRITZ!Box reports signal quality as MSE (Modulation Error Ratio) using negative dB values. DOCSight uses the absolute value for comparison with standard SNR/MER thresholds.

Bridge Mode

Called "exposed host" or "IP client" mode on the FRITZ!Box. DOCSight continues to work in this configuration as long as the FRITZ!Box web interface remains reachable.

Status: Supported

Related

• Adding Modem Support
• Reference Values (note the FRITZ!Box +6 dB offset explanation)
• Bridge Mode Compatibility