ABSTRACT: GR-181 replaces TR-TSY-000181, Issue 1, March 1987, but contains NO TECHNICAL CHANGES from that original document. It has been issued strictly to conform with the new Telcordia Technologies document format and GR process, and carries a new issue number and date.

Dual-Tone Multifrequency (DTMF) signaling uses voiceband tones to send address signals and other digital information from push-button telephones and other Customer Premises Equipment. A primary application of DTMF signaling is customer dialing into an end-office switching system in a Local Access and Transport Area (LATA). Other uses are intra- and inter-PBX (Private Branch Exchange) into LATA end-office switches.

GR-506, LSSGR: Signaling, covers receiver requirements for DTMF signaling into the serving end-office switch. However, it has become necessary to enlarge the scope of DTMF receiver requirements to include end-to-end signaling over multiple voice links switched in tandem. This capability is necessary whenever customer-generated DTMF signals are sent, without regeneration, beyond the originating end-office switch (e.g., to remotely access or control a new network feature).

This GR provides the Telcordia view of generic requirements that should be met by a receiver to meet the needs of a typical Local Exchange Carrier (LEC) for local signaling and end-to-end signaling across networks.

When using GR-181, you may need to refer to GR-506, LSSGR: Signaling and SR-2275, Telcordia Notes on the Networks.