Internet / DSL Information / Spectrum

This page presents diagrams that represent the signal-to-noise ratio and the modulation depth of the carrier frequencies.

Click on the "Refresh" button to view the current values.

Signal-to-noise ratio

The upper diagram shows the signal-to-noise ratio at each individual downstream carrier.


The lower diagram is a graph of the modulation depth. The higher the modulation depth, the more bits per time unit are transmitted by the carrier.

A carrier corresponds to a frequency band of 4312.5 Hz. The ADSL transmission range is subdivided into 256 carriers, of which 32 may be used for upstream (to the Internet) and 190 for downstream transmission.

The red marking indicates the pilot tone which is used to synchronize the DSL-Controller with the exchange.

Line Branching

Line branching is when there are branches in the telephone cabling between the DSL mulitplexer (DSLAM) and the FRITZ!Box.

Whenever the FRITZ!Box detects branching, the branches found are displayed in the two diagrams.

Repeated malfunctions originating in one branch are also displayed.