The Apple Modem Updater will update modems in the PowerBook G3 Series, iMac, Power Macintosh G3 (Blue and White), and Power Macintosh G4 (PCI and AGP) computers. The updater installs version 2.3 of the Conexant firmware which contains the latest versions of both the V.90 and the K56flex protocols. The modems can use either the K56flex or V.90 protocols and will automatically negotiate with the service provider to use the appropriate one.
After you have updated the modem you may notice that the connection speed that is reported when you first establish a connection may be lower than it was prior to the upgrade, however the modem throughput will be at least as good and often better than before the upgrade. Throughput is the measure of how quickly a certain amount of data is transferred from one modem to another. It is important to remember that the connection speed that is reported is only the initial connection speed. The modems will adjust their communications speed as line conditions require. A faster connection speed does not necessarily indicate a higher throughput, factors like resending data due to noise on the phone lines will lower overall throughput.