When installed, Windows 95 configures your serial ports (COM1 and COM2) to a default speed of 9600 bps (bits per second) using Xon/Xoff (software) flow control. This means that the speed of data flow between your PC and your modem is limited to a slow speed of 9600 bps, and that the flow of data is regulated by software commands.

With the speed of modern modems, these settings are quite inadequate for high speed modem communications. If you have a 28800 bps or 33600 bps modem we recommend that you modify these settings to use optimal values. If you have a modern machine, your Pentium (or high-end 486) motherboard may have on-board serial (COM) ports fitted with NS16550 UART (Universal Asynchronous Receiver Transmitter) chips. The 16550 is a 16-byte FIFO (first in, first out) buffer which buffers data flowing to and from your PC to and from your modem.

If you have a 16550 UART (this is essential for high speed communications under Windows), it is advisable to make use of your serial port's ability to buffer data at a high speed.

To do this, click the Start menu, click Settings and click Control Panel. Once the Control Panel appears, double click the System icon and click on the Device Manager tab.

Scroll down to the Ports (COM & LPT) entry and click the adjacent plus (+) sign. Click the serial port to which your modem is connected, and click the Properties button.

Click the Port Settings tab and set the Bits per second rate to a minimum of 38400 bps (if you have a 28800 or 33600 bps modem). Your serial port might support speeds up to 115200 bps, in which case you can adjust the setting to a higher value. Change the Flow control to Hardware and click OK. Click OK once more to exit the system properties screen.