Facsimile store and forward system with local interface translating DTMF signals into store and forward system commands

摘要

A local router interface couples a conventional facsimile device to the public switched telephone network (PSTN) to communicate with a remotely located facsimile store and forward facility (F-SAFF) to perform a host of improved facsimile service methods, including a never no answer or busy send (NNABS) method, a never no answer receive (NNAR) method, a private facsimile method, a will call facsimile method, a pager facsimile method, a facsimile mail method, a facsimile information retrieve method, a facsimile information send method, a facsimile cover method, a facsimile speed cover method, a facsimile broadcast method, a facsimile flexible broadcast method, a facsimile access restriction method, a facsimile conversion method, an urgent facsimile method, and a facsimile addition method. Innocuous call progress monitoring with fast busy detection, post-fax line holding, F-SAFF-to-remote and remote-to-F-SAFF bridging are provided. The router includes detectors for loop-current, ring signals, call progress signals, precise busy signals, dual tone multi-frequency (DTMF) signals, and modulated data signals, as well as generators for going off-hook, generating and transmitting DTMF signals and modulated data signals over a wall phone line as well as ring and dial tone signals through an adjustable amplifier circuit and a subscriber line interface circuit to a fax telephone line. A switching connection circuit is also included for selectively connecting the wall phone line to the fax phone line and for selectively connecting other components of the telephony interface thereto.