Preventing the dialling or sending of predetermined telephone numbers or selected types of telephone numbers, e.g. long distance numbers

Substation equipment, e.g. for use by subscribers > with means for preventing unauthorised or fraudulent calling > Preventing the dialling or sending of predetermined telephone numbers or selected types of telephone numbers, e.g. long distance numbers

Substation equipment, e.g. for use by subscribers (subscriber services or facilities provided at exchanges H04M3/00; prepayment telephone coin boxes H04M17/00; current supply arrangements H04M19/08) > with means for preventing unauthorised or fraudulent calling (verifying user identity or authority in secret or secure digital communications H04L9/32) > Preventing the dialling or sending of predetermined telephone numbers or selected types of telephone numbers, e.g. long distance numbers