Black Box SW927C manual Serial Port Control Utility, Admode COMn baud, parity, databits, stopbits

MODULAR SMART SWITCH

6.10.2CHANGING THE TIMEOUT

The timeout period can be varied from the default of 16 seconds to any value between 1 and 255 seconds, or it can be permanently off. To do so, select the TIMEOUT option and type the required value into the entry box. Press <enter> to return to the options menu. To return to the default value of

16 seconds, press <escape>.

6.10.3SELECTING A PC PORT

If the correct PC port is not shown on the main menu (G in Figure

6-1), then use the PC PORT option to select this. Highlight the PC PORT option and type <enter>. Use the <up> and <down> cursor keys to select the desired port (highlighted) and then press <enter>. The PC port you have selected will now be displayed.

NOTE

The control software defines the routing from the selected port on your PC—it does not set the port that your software will use for output.

MODULAR SMART SWITCH

7. Serial Port Control Utility

The control software allows serial ports on IBM compatible PCs to be run at the high baud rates supported by the Modular Smart Switch. The utility can be used to control COM1 or COM2 and supports a wide range of protocols. The time-saving advantages of running serial ports at higher baud rates can be quite dramatic, and the control software makes sure that the correct protocol is used regardless of the settings on the application program.

Although DOS will normally only support baud rates up to 9600, most PCs are capable of running at much higher speeds of 19,200, 38,400, or 57,600 baud. A number of high-baud-rate utilities are available that act like the DOS MODE command. But these can be of little practical use, since many application programs change the baud rate and protocol when they run.

The control software overcomes this problem by preventing application programs from changing the baud rate or protocol of the serial port being controlled. This has two major advantages. First, the user does not need to worry about setting the baud rate and protocol in the application program. Second, high baud rates can be used for plotting from packages that would normally only support lower baud rates.

To run the control software, copy the program ADMODE.COM from the utility disk to a suitable directory on your PC. At the DOS prompt, type a command in the following format.

ADMODE COMn: baud, parity, databits, stopbits

You only need to include a parameter after baud if it needs to be changed from the default values shown in Table 7-1. The minimum command syntax is:

ADMODE COMn: baud

Example

To set serial port 1 (COM1) to 38400 baud, 8 data bits, 1 stop bit, and no parity, use the following command.

ADMODE COM1:38400,N,8,1 <enter>

High-Baud-Rate Limitations

In practice, almost all modern PCs will support baud rates of 38,400. However, a number of PCs that we tested were not able to support baud rates of 57,600 because of the design of their serial ports. If you have problems with particular PCs, try reducing the baud rate.

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