Abstract: A method which, in response to an alerting signal from a source, manages a data transfer from the source, via a communications link, to at least two terminals coupled with the communications link. The method (a) dynamically designates one of the at least two terminals as a token terminal, (b) generates an acknowledgment signal with the token terminal, and (c) terminates the communications link during the data transfer with the token terminal. The dynamic designation of the token terminal is performed by (a) assigning a time delay for each of the terminals, and (b) determining, with each of the terminals, after the assigned time delay, whether the terminal will accept the data transfer from the source based on a condition of the communications link.

Abstract: A method and apparatus for detecting a dual tone alerting signal in the presence of speech for the purpose of initiating transfer of special service information on a telephone line is described. The apparatus includes two channels for separately detecting each tone. Each channel includes means for comparing the signaling energy around one of the tones with the energy in a selected weighted guard band portion of the voiceband. Based on this comparison, a determination is made whether a tone is or is not present. A pulse signal formed from the coincidences of tone detection in each channel is used by timing circuitry to determine whether the dual tone alerting signal is actually present or whether speech energy caused both tones to be erroneously detected (talkoff). Characteristics of this pulse signal are analyzed to determine whether an alerting signal is present.