COM port

The redox potential for the (por)Com/ /(porT)Com/ couple is more negative than the corresponding (por)Fe 1/ /(porT)Fe111/ couple (Table 13.8). In contrast to alkyl-iron porphyrins, (po Co111/ is not reduced by the (por)Co anion. Instead, it is reduced to (porT)CoUI7 anion by a more negative scan (Em, -1.17 to -1.36 V). 

Note that COM 1 and COM 3 share the same interrupt, as do COM 2 and COM 4. The pairs are differentiated by using different I/O addresses for the different COM ports. This can work without conflict. The only problem is if you connect two devices that need to use an interrupt to the COM ports that use the same interrupt (for example, a mouse on COM 1 and a modem on COM 3). When this happens, the devices will work separately, but if you try to use both at the same time (for example, use the mouse while downloading a file with the modem), they will conflict and problems will occur. 

One disadvantage to the serial mouse is that it uses a COM port. If the computer had only one COM port, that was it— you couldn t use any other peripheral devices. Also, if you had another COM port but it was on a shared interrupt, that other COM port couldn t be used for another communication device (like a modem) as long as data was coming into the computer on the COM port being used by the mouse. So, in a manner of speaking, a serial mouse really takes up two COM ports. For example, because COM 1 and COM 3 both share Interrupt 4, when you put a mouse on COM 1 you are also preventing the use of COM 3. 

Although the bus mouse had a faster interface, speed wasn t really an issue. The mouse signals didn t really overload the interface. The major advantage to a bus mouse, compared to a serial mouse, was that it didn t take up a COM port. This allowed systems that were short on COM ports to add a mouse. The one downside was that the bus card does use an interrupt (and it can only use IRQ 2, 3, 4, or 5). 

They usually use a COM port or bidirectional parallel port instead of SCSI to transfer their data. They are limited in their quality, however, and generally should not be used in graphics work. 

There are two types of modems internal and external. Internal modems are installed as expansion cards inside a computer. External modems have their own power supplies and connect to an external COM port with an RS-232 cable. There are advantages and disadvantages to each. 

Internal modems are usually smaller and cheaper than their external counterparts. However, they are more difficult to configure. You need to configure them to use an unused COM port. Table 6.3 lists the IRQ and FO port addresses of the standard COM ports installed. 

If you can t type anything, you either don t have the right COM port selected for the modem or you have half-duplex mode enabled. To address this problem, you must enter "ATF1," then press Enter. The modem should return the message "OK" and you will now be able to see your commands. 

A serial device server connects the serial port to the network. The device server is a piece of hardware that provides an IP address, thns making the serial device act like a compnter in the network. Conseqnently, no additional compnter is needed, and the device can be plngged directly into the network. Some device servers optionally provide a virtnal serial port, which makes the serial device behave like a computer with a standard COM port. 

The group data, by one machine to the USB port to PC intelligent gas content prediction system. Run the PC software, set the COM port and baud rate, input to upload data from the instrument category, run the upload menu. PC interface is shown in Figure 3. 

This GUI based software is flexible in such a manner that it has the option for COM PORT selection, if the number of COM PORT of the peripheral device/hardware to which the client is connected is not known or changes. It can be switched on or off as well. 

The string data type is used to represent a sequence of ASCII characters. The string data types are commonly used to send and receive text messages fixtm user or any other communications port such as COM ports, Ethernet ports, etc. Apart from string control and string indicator, various objects that support string data type such as table, hst box, etc. are available. 

Fig. 4 Operation chart for controlling and acquiring data via COM port...

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