COM ( hardware interface ) - wikipedia COM ( hardware interface ) This article needs additional citations for verification. Please help improve this article by adding citations to reliable sources. Unsourced material may be challenged and removed. ( September 2013 ) COM ( Communication port ) is the original, yet still common, name of the serial port interface on IBM PC - compatible computers. It might refer not only to physical ports, but also to virtual ports, such as ports created by Bluetooth or USB - to - serial adapters. Contents 1 History 2 I / O addresses 3 See also 4 References 5 Further reading 6 External links History Most PC - compatible computers in the 1980s and 1990s had one or two COM ports. As of 2007, most computers ship with one or no physical COM ports. As of 2014, most PC - compatible computers do n't include any COM ports. A lot of them do still include a COM header. After the RS - 232 COM port was removed from most IBM PC compatible computers in the 2000s, an external USB - to - UART serial adapter cable was used to compensate for the loss. A major supplier of these chips is FTDI. I / O addresses The COM ports are interfaced by an integrated circuit such as 16550 UART. This IC has seven internal 8 - bit registers which hold information and configuration data about which data is to be sent or was received, the baud rate, interrupt configuration and more. In the case of COM1, these registers can be accessed by writing to or reading from the I / O addresses 0x3F8 to 0x3FF. If the CPU, for example, wants to send information out on COM1, it writes to I / O port 0x3F8, as this I / O port is `` connected '' to the UART IC register which holds the information that is to be sent out. The COM ports in PC - compatible are typically defined as : COM1 : I / O port 0x3F8, IRQ 4 COM2 : I / O port 0x2F8, IRQ 3 COM3 : I / O port 0x3E8, IRQ 4 COM4 : I / O port 0x2E8, IRQ 3 See also Device file Parallel port Serial port Input / Output Base Address References Jump up ^ `` Configuring a communication port ''. IBM Lotus Domino and Notes Information Center. Retrieved 17 September 2013. Jump up ^ Products ; FTDI. Further reading Serial Port Complete : COM Ports, USB Virtual COM Ports, and Ports for Embedded Systems ; 2nd Edition ; Jan Axelson ; Lakeview Research ; 380 pages ; 2007 ; ISBN 978 - 1 - 931 - 44806 - 2. External links How to Interface Hardware in COM ports Java Simple Serial Connector - library for work with serial ports from Java. Support Windows : Win98 - Win8 ( 32 - bit and 64 - bit ), Linux ( x86, x86 - 64, ARM ( soft and hard float ) ), Mac OS X : 10.5 - 10.8 ( x86, x86 - 64, PPC and PPC64 ), Solaris OS ( x86, x86 - 64 ). Retrieved from `` https://en.wikipedia.org/w/index.php?title=COM_(hardware_interface)&oldid=795482832 '' Categories : Computer buses Hidden categories : Articles needing additional references from September 2013 All articles needing additional references Talk Contents About Wikipedia Čeština עברית Polski Edit links This page was last edited on 14 August 2017, at 14 : 39. About Wikipedia

Question: which i/o address is used by the com2 port
Answer: I/O port 0x2F8