F12
12kHz Billing Tone Filter
Billing Tones or metering pulses generated by the telephone exchange can cause modem connection difficulties. The billing tone is typically 12kHz or 16KHz. The F12 dongle allows the modem to work without degradation in the presence of 12kHz pulses. For 16kHz pulses use the F16 dongle.
12KHz pulses are in use in:
- Austria
- Denmark
- Hungary
- Iceland
- Ireland
- Italy
- Portugal
- Sweden
- Switzerland