Written by Amber

Caller ID: the difference between DTMF and FSK

Is number recognition a requirement for your home telephone? Then your device must be compatible with the type of number recognition with which your provider operates and the option must be enabled in your subscription. There are 2 types of caller ID: DTMF and FSK. In this article I explain what these two types entail and what the difference between them is.


There are two types of number recognition: via the regular fixed line you have to deal with DTMF, via cable telephony we speak of FSK. DTMF is only supported in the Netherlands and FSK in both the Netherlands and Belgium. In addition, DTMF works exclusively with KPN, while FSK works with all other providers.

The differences


DTMF providers

DTMF is short for Dual Tone Multi Frequency. In the Netherlands, KPN is the only provider that uses DTMF for number recognition. If you have a subscription with KPN and a fixed telephone that supports FSK, number recognition does not work via the KPN network. Do you always want to be sure of number recognition at KPN? Then choose a fixed telephone that supports both DTMF and FSK.


FSK providers

FSK stands for Frequency Shift Keying and is used by providers such as Ziggo and Tele2. In Belgium too, mainly FSK is used. Compared to DTMF there are more possibilities at FSK than just number display. This way the name display can also be sent. If in doubt, always contact your provider. ** Please note: ** phones support FSK and / or DTMF only in the countries for which they were designed.

Article by:
Amber Landline Phone Expert.

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