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Serial Port Diagnosis in Windows XP: A Simple Method



You can check multiple ports at the same time by opening multiple sessions, putting the loopback adapter on one port, and trying to type into each session. When you can see what you are typing, you know that the COM port is working and you can see which port number the physical serial port is. Close the window for the port that you just tested to speed up the testing of the remaining serial ports.




how to test serial port in windows xp



One way to test a serial port is to use a Port And Peripheral Electronic Reactive Communications Link Interface Probe - otherwise known as a paperclip, bend it so it can be inserted in positions 2 and 3 of a female serial port connector, this provides a loopback circuit that should echo back any characters sent to the com port (it relies on the serial drivers not being fussy about other data lines like DSR, RTS etc). You can probably still get RS232 test widgets.


The device does not have a device driver: When a device driver for a device is not available, Device Manager displays the device as Unknown Device and puts it in the Other devices branch. This is very common with universal serial bus (USB) and Institute of Electrical and Electronics Engineering (IEEE) 1394 composite devices. Also, a status of Error Code 1 or Error Code 10 may be displayed when you view the properties of the device in Device Manager.Note Most USB and IEEE 1394 devices function correctly without additional device drivers because they are configured by the drivers that are included with Windows for these bus types. However, an additional device driver is needed if the device does not fit the defined and supplied Windows class drivers. If the bus cannot identify the device, it interprets the device as a composite device and then reports it as such in Device Manager.


View the Setupapi.log fileIf the device has a meaningful name, use the information in the Setupapi.log file to determine the cause of an unknown device. By default, the Setupapi.log file is located in the %SystemRoot% folder.Sometimes the listed device name can be misleading. For example, a device may be listed as a serial device in Device Manager, when in reality it is not related to a serial port. This typically occurs when a partial Plug and Play ID is available, and Device Manager interprets it as a serial device. This interpretation may occur because of a compatible ID specified by the device. Again, this can be corrected by locating the startup program that may not be behaving correctly.Be aware that merely removing the unknown device in Device Manager does not work if a software program is the cause of the unknown device. You must remove the program and then restart your computer. If the unknown device is still listed in Device Manager after you restart your computer in safe mode, contact Microsoft Customer Support Services for help in removing the device.


Installing section epatapi_inst from C:\documents and settings\user name\my documents\parallel port test drivers\epatapnt.infAn unsigned or incorrectly signed driver (C:\documents and settings\user name\my documents\parallel port test drivers\epatapnt.inf) was installed for Parallel ATAPI Adapter.. Error 0xe000022f: The third-party INF does not contain digital signature information.Copying file C:\documents and settings\user name\my documents\parallel port test drivers\epatapnt.mpd to C:\Windows\System32\DRIVERS\epatapnt.mpd.An unsigned or incorrectly signed driver (C:\documents and settings\user name\my documents\parallel port test drivers\epatapnt.mpd) was installed for Parallel ATAPI Adapter.. Error 0xe000022f: The third-party INF does not contain digital signature information.


For most of these operating systems two types of driver are available: Virtual COM Port (VCP) drivers and direct (D2XX) drivers. The VCP driver emulates a standard PC serial port such that the USB device may be communicated with as a standard RS232 device. The D2XX driver allows direct access to a USB device via a DLL interface.


If you can access the registry, the HKEY_LOCAL_MACHINE\HARDWARE\DEVICEMAP\SERIALCOMM key contains a list of COM ports Windows currently supports (in some cases, this information may be stale/incorrect; like, I suspect, when a plug & play device providing serial ports has not completed detection/installation or has been recently removed).


Portmon is a utility that monitors and displays all serial andparallel port activity on a system. It has advanced filtering and searchcapabilities that make it a powerful tool for exploring the way Windowsworks, seeing how applications use ports, or tracking down problems insystem or application configurations.


Portmon understands all serial and parallel port I/O control (IOCTLs)commands and will display them along with interesting informationregarding their associated parameters. For read and write requestsPortmon displays the first several dozen bytes of the buffer, using'.' to represent non-printable characters. The Show Hex menu option letsyou toggle between ASCII and raw hex output of buffer data.


The Portmon GUI is responsible for identifying serial and parallelports. It does so by enumerating the serial ports that are configuredunder HKEY_LOCAL_MACHINE\Hardware\DeviceMap\SerialComm and theparallel ports defined underHKEY_LOCAL_MACHINE\Hardware\DeviceMap\Parallel Ports. These keyscontain the mappings between serial and parallel port device names andthe Win32-accessible names.


When you select a port to monitor, Portmon sends a request to itsdevice driver that includes the NT name (e.g. \device\serial0) thatyou are interested in. The driver uses standard filtering APIs to attachits own filter device object to the target device object. First, it usesZwCreateFile to open the target device. Then it translates thehandle it receives back from ZwCreateFile to a device objectpointer. After creating its own filter device object that matches thecharacteristics of the target, the driver callsIoAttachDeviceByPointer to establish the filter. From that point onthe Portmon driver will see all requests aimed at the target device.


Portmon has built-in knowledge of all standard serial and parallelport IOCTLs, which are the primary way that applications and driversconfigure and read status information from ports. The IOCTLs are definedin the DDK file \ddk\src\comm\inc\ntddser.h and\ddk\src\comm\inc\ntddpar.h, and some are documented in the DDK.


On Windows 95 and 98, the Portmon GUI relies on a dynamically loadedVxD to capture serial and parallel activity. The Windows VCOMM (VirtualCommunications) device driver serves as the interface to parallel andserial devices, so applications that access ports indirectly use itsservices. The Portmon VxD uses standard VxD service hooking tointercept all accesses to VCOMM's functions. Like its NT device driver,Portmon's VxD interprets requests to display them in a friendlyformat. On Windows 95 and 98 Portmon monitors all ports so there is noport selection like on NT.


Check in device manager for the presence of serial pointing devices, andcheck which comm port they are using. If you find one, click properties andchoose disable. If you delete it Windows will re-install it.


You would be correct. I am running an instance of each of those softwares. Within the SMC60WIN I had to tell the software which COM port to use and I used the port that was shown in the device manager which was COM2. After getting that to work I plugged in the second usb to serial adapter for the data collection box. I have to do the same thing for this device as well. I went in and had to tell the software which COM port to use which was COM7. If I go into the device manager and look under ports as you have shown. In the description, the parentheses it lists COM7 for both devices. I do not recall having to change this in device manager, only in the software.


The Windows connector provides serial device mapping, which enables users to access external serial devices connected to a Sun Ray Client or an Oracle Virtual Desktop Client running on a Windows client computer. When initiating the Windows connecter, you need to configure the device mapping through the -r comport: option of the uttsc command.


Technical support recommends using the Pepperl+Fuchs Comtrol, Inc. Utility to verify that the RocketPort EXPRESS SMPTE is functioning properly.Test Terminal (Wcom2) and Port Monitor (Pmon2) are packaged in the utility and can be used to test the serial ports.


Using Test Terminal and a loop-back plug on a port will help test serial ports and verify port operation byallowing you to send data out the port on the transmit side, loop the data back to the receive side and view thereceived data on the screen.


A virtual COM port or a virtual serial port is an ideal solution when a legacy software application expects a connection to a serial device port (COM port or COMM port) but cannot connect, due to a physical lack of available serial ports. Instead, we reconfigure the computer to send serial port data over a local area network or the Internet as if over a true serial port. When the legacy application attempts to send data to a serial COM port, it is actually transmitted through the virtual serial port over a TCP/IP connection. Information sent back to the legacy application also travels over the network where it is received by the virtual serial or virtual COM port, and is then finally passed to your legacy application.


Important Note: This tutorial deals exclusively with a virtual COM port implementation that is used with NetBurner devices. If you are looking for a native software solution to create virtual COM ports for use with other systems or hardware, we suggest the Virtual Serial Port over Ethernet Connector or the Virtual Serial Port Driver from our partners at Eltima Software. They are both incredibly stable and versatile utilities that support various Windows versions, up to the latest Windows 10. 2ff7e9595c


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