1. Transmission of alphanumeric caller id information using dtmf signalling

2. Simply the dialled telephone number is analysed to determine the activation of the DTMF or not.

3. Provision and operation of voice and dual tone multi-frequency (DTMF) response systems for handling information and business transactions

4. Additionally, it establishes a common technical regulation covering the attachment requirements for analogue PSTN terminal equipment, where network addressing, if provided, is by means of DTMF.

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6. Single-chip microcomputer of C-MOS technology, consisting of an arithmetical logic unit (ALU) with an organization of four bits, a read-only memory (ROM) with a storage capacity of 2 K × 8 bits, a dual-tone, multi-frequency (DTMF) generator, a random access memory (RAM) with a storage capacity of 1 Kbit, whether or not with another random access memory (RAM) with a storage capacity of 512 bits, in the form of a monolithic integrated circuit, contained in a housing the external dimensions of which do not exceed 16×54 mm, with not more than 42 connecting pins and bearing: