A modem (modulator-demodulator) apparatus provided with modem circuits having different signal processing standards, which is optimized for a facsimile machine. Switching of modem functions can be accurately performed by concurrently operating modems with required standards selected from modems with...http://www.google.com.tw/patents/US5233627?utm_source=gb-gplus-share專利 US5233627 - Multimode modem for facsimile
