One of the oldest standards for serial asynchronous digital information exchange is RS-232. Its implementation in a PC is done through a special connector - a COM port. Despite the availability of new and faster communication methods, the COM port is still used, in particular, when a modem is operating. Sometimes, in this case, it is necessary to synchronize the speed of receiving and transmitting data in order to avoid information loss. You can set the required COM port speed both programmatically and using standard Windows OS tools.
Instructions
Step 1
When working with a modem, change the COM port speed in the device parameter settings. To do this, in the "Start" menu, select "Control Panel" and open the "Phone and Modem Options" shortcut. In the window that appears, in the "Modems" tab, select the desired device and click on the "Properties" button.
Step 2
Go to the "Modem" tab and in the "Modem port speed" drop-down list, set the desired baud rate for the used COM port. This parameter is not an indication of the maximum speed of the modem connection. But by changing the value, you will set the connection speed, which the modem will not be able to exceed when connected.
Step 3
To change the speed of another COM port, go to the "Additional communication parameters" tab. Click on the "Additional parameters" button and in the window that appears, select from the "COM port number" drop-down list the device that you need to use for communication using a modem. Please note that this feature is relevant only if you physically switched the modem cable to the connector of another COM port.
Step 4
In the Advanced Communication Settings tab of the previous Modem Properties dialog box, click the Change Defaults button. A window will appear on the screen, go to the "General" tab, where there are elements with call and data line connection parameters. In the "Port speed" drop-down list, set the required maximum communication speed for data transmission through the modem.
