A cellular modem pool provides a "transparent call progress" feature where each modem pair of the cellular modem pool is coupled to a cross-connect switch, which communicates call progress information between the cellular-side and the PSTN-side during data call setup. The modem pair of the cellular modem...http://www.google.de/patents/US5920825?utm_source=gb-gplus-sharePatent US5920825 - Method and apparatus for bypassing a cellular modem pool during a fax transmission
