A collection of these drivers for kernel 2.4.x can be found on Jan Stifter's Unofficial PCTEL modem for Linux site.
PCT301D 16-pin SOIC PCT301L 16-pin SOIC PCT303D 16-pin SOIC PCT303L 16-pin SOIC PCT303W CODEC/World DAA phone-line interface 16-pin SOIC PCT789T ASIC PCT789T-A ASIC 100-pin TQFP PCT789T-C ASIC 100-pin LQFP PCT1789 = PCT789T + PCT301D + PCT301L PCT1789N = PCT789T-A + PCT303D + PCT303L PCT1789W = PCT789T-C + PCT303D + PCT303W