The fastest it has ever connected to 955-0056 is 33.6Kbps. Third, the above also presumes a 16550 UART chip in your micro. The UART chip is between your micro's BIOS and your modem. The 16550 UART chip has a 16 byte FIFO buffer. Older micros may have a 8550 UART chip with a 2 byte FIFO buffer, a size that can easily be overrun.
Overruns result in errors and retries that slow the effective data flow rate.
If you are running NT, your UART chip is almost certainly a 16550. Fourth, the quality of the phone line from your residence to BS on SW 2nd Avenue will also affect the actual speeds. By slowing the rate the number of errors and, therefore, retries will be reduced. Increasing the rate also increases the number of errors and retries on a noisey line. A number of settings, perhaps starting in the middle, with upload and download trials can give an approximate optimal rate balancing the set speed and retries for the best overall data trasfer rates.