The Caller ID service delivers the number of the calling party to be shown on the display of your handset or to be added to a voice mail left on your voice mailbox. Quadro supports two types of Caller ID notification: FSK and DTMF.

The FSK (Frequency Shift Key) standard supports caller ID indication either with the phone handset on-hook or if the called party is already busy with another call or operation (handset is off-hook). For internal calls caller ID notification in FSK can show up two lines of identifiable parameters on the called phone display. The first line shows caller's extension number. The second line shows the information that is set as Display Name on the page Extensions Management - General Settings. For external IP calls caller ID notification in FSK can also show up two lines of identifiable parameters on the called phone display. The first line shows the caller's user name. The second line shows the caller's nickname (if indicated in configuration). If the nickname not available and there is a display name, provided by the caller party, the second line will display it, otherwise the URL, in the format: username@host will be displayed. For calls from the PSTN network the entire caller ID message will be shown.

The DTMF (Dual Tone Multi Frequency) standard supports caller ID indication only if the phone handset is on-hook (phone is free and ready to accept calls). This standard has also caller ID notification conditions but they are non-configurable. Caller ID notification in DTMF can show only one line of identifiable parameters on the called phone display. For internal calls it is caller's extension number. For external IP calls it is the caller's user name. For calls from the PSTN network caller ID will only display the caller's phone number.

Note: DTMF supports only parameters consisting of digits. If any letter symbol has been used in the external caller user name, DTMF will not display caller ID.