International call progress tones for IP-PBX and VoIP telephony

Telephone Line Signalling

Billing silence

  • The billing silence ensures the unhampered exchange between telephone central offices of tone encoded billing information.
  • When a modem answers an incoming call, no data shall be transmitted for at least two seconds.
  • Most modems already have this feature built into them.

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Related product: CPT-Master tone generator app