PDF manual - Virtual Null Modem
Contents
1. GY P VIRTUAL NULL MODEM CONNECTING UNCONNECTABLE USER S MANUAL 2004 2007 AGG Software Virtual Null Modem 2004 2007 AGG Software All rights reserved No parts of this work may be reproduced in any form or by any means graphic electronic or mechanical including photocopying recording taping or information storage and retrieval systems without the written permission of the publisher Products that are referred to in this document may be either trademarks and or registered trademarks of the respective owners The publisher and the author make no claim to these trademarks While every precaution has been taken in the preparation of this document the publisher and the author assume no responsibility for errors or omissions or for damages resulting from the use of information contained in this document or from the use of programs and source code that may accompany it In no event shall the publisher and the author be liable for any loss of profit or any other commercial damage caused or alleged to have been caused directly or indirectly by this document Printed Naf e t 2007 Publisher AGG Software Production 2004 2007 AGG Software http www aggsoft com Contents l Table of Contents Part 1 Introduction 1 ADOUL SOIWATE E E E E A E E E E E E E A nue s2 ed can qnue 1 License Registration and technical support 2 MACON SO uge EEN 2 HOW to register ccsseeecc2. By default Virtual Null Modem will be installed to the directory Programs Files Virtual Null 2004 2007 AGG Software Installation Modem of your system disk but you can change this path Microsoft Windows 2003 notes During installation Windows will ask your permission twice to install the kernel mode driver fig 1 Please set click the Yes button Security Alert Driver Installation Fig 1 Windows 2003 popup Microsoft Vista notes Before install Windows will ask your permission to install the software fig 1 Please click the Continue button A program needs your permission to continue If you started this program continue fe Virtual Null Modem 2 5 0 6 setup AGG Software Y Details L God User Account Control helps stop unauthorized changes to your computer 2004 2007 AGG Software 7 Virtual Null Modem Fig 2 Vista popup During installation Windows will ask your permission to install the kernel mode driver fig 2 Please set the Always trust software from AGG Software option and click the Install button 2 Windows Security ES Would you like to install this device software Name AGG Software http www aggsoft com Sy UAW Publisher AGG Software d Always trust software from AGG Software Install Don t Install E You should only install driver software from publishers you trust How can I decide which device software is safe t
3. e No reboot required Creating installing and removing of virtual serial ports occurs at real time You can create any number of virtual serial ports pairs Any other hardware or virtual serial ports are not used or occupied You even can have no serial ports in your system Other applications will never see the difference between real serial port and virtual serial 2004 2007 AGG Software Introduction 2 ports created by Virtual Null Modem software e The link between two virtual serial ports is faster then real null modem cable connection and depends on your computer system speed e The virtual link is much more reliable than common physical link e Virtual Null Modem uses kernel driver technology and supports WDM WMI Power Management PNP etc e Virtual Null Modem software has a simple menu driven step by step set up Programming is not required to configure the software to configure virtual serial ports and virtual serial ports pairs e If you are software developer then you can configure each port to sumulate a real world data exchange with errors in data e You can add remove virtual null modems from your application by using a command line interface DISCLAIMER We take no responsibility for any damage or injury caused by files written or edited with this software As the user has twenty one days to try this software with the full function demo version warranty is limited to replacement of de
4. the transfer must include the update and all previous versions Whilst every care has been taken in the construction and testing of this software it is supplied subject to the condition that the user undertakes to evaluate the suitability of the control for his her purposes AGG Software makes no representation of the software s suitability for any purpose and the user agrees that AGG Software has no responsibility for any loss or damage occasioned by the use of this software TO THE MAXIMUM EXTENT PERMITTED BY APPLICABLE LAW THE SOFTWARE AND DOCUMENTATION ARE PROVIDED AS IS AND AGG SOFTWARE DISCLAIMS ALL OTHER WARRANTIES AND CONDITIONS EITHER EXPRESS OR IMPLIED INCLUDING BUT NOT LIMITED TO IMPLIED WARRANTIES OF MERCHANTABILITY FITNESS FOR A PARTICULAR PURPOSE CONFORMANCE WITH DESCRIPTION TITLE AND NON INFRINGEMENT OF THIRD PARTY RIGHTS TO THE MAXIMUM EXTENT PERMITTED BY APPLICABLE LAW IN NO EVENT SHALL AGG SOFTWARE BE LIABLE FOR ANY INDIRECT INCIDENTAL CONSEQUENTIAL SPECIAL OR EXEMPLARY DAMAGES OR LOST PROFITS WHATSOEVER INCLUDING WITHOUT LIMITATION DAMAGES FOR LOSS OF BUSINESS PROFITS BUSINESS INTERRUPTION LOSS OF BUSINESS INFORMATION OR ANY OTHER PECUNIARY LOSS ARISING OUT OF THE USE OR INABILITY TO USE THE SOFTWARE PRODUCT EVEN IF AGG SOFTWARE HAS BEEN ADVISED OF THE POSSIBILITY OF SUCH DAMAGES IN ANY CASE AGG SOFTWARE S CUMULATIVE AND ENTIRE LIABILITY TO YOU OR ANY OTHER PARTY FOR ANY LOSS OR DAMAGES RESULTING
5. FROM ANY CLAIMS DEMANDS OR ACTIONS ARISING OUT OF OR RELATING TO THIS AGREEMENT SHALL NOT EXCEED THE PURCHASE PRICE PAID FOR THIS LICENSE Should any term of these terms and conditions be declared void or unenforceable by any court of competent jurisdiction such declaration shall have no effect on the remaining terms hereof If you do not agree to these conditions you should not install this software 2 2 How to register Full version Single user license 40 EUR per license Corporate order of 6 10 license 35 EUR per license More than 11 licenses 30 EUR per license 2004 2007 AGG Software License Registration and technical support 4 Site license registration fee 675 EUR 2 3 Limitations Trial version 21 days trial limit 65k of traffic Rregistered version No limitations 2 4 Support Virtual Null Modem questions support aggsoft com Sales questions sales aqgsoft com 3 Installation 3 1 System requirements Processor Any Intel x86 compatible CPU Operating system Windows 2000 Windows 2000 Server Windows XP all editions both x86 and x64 Windows 2003 Server both x86 and x64 Windows Vista both x86 and x64 The program doesn t work under Windows 9x Me and NT CPU speed Recommended 1 GHz or faster our software may run successful on certain slower CPUs but because of Windows overhead performance test results will not be as accurate Memory Recommen
6. SerialNo Plugs in a virtual serial port device with number SerialNo SerialNo must be greater than zero You should plug in 2 devices for creating one virtual null modem device u SerialNo or 0 Unplug a virtual serial port device with number SerialNo Please specify 0 to unplug all devices enumerated so far e SerialNo or 0 Eject a virtual serial port device with number SerialNo Please specify 0 to eject all the devices enumerated so far i lt INF_File gt lt Hardware_ID gt Install device driver INF_File for device Hardware ID ia Install all Virtual Null Modem s devices drivers r lt Hardware_ID gt Remove device Hardware ID ra Remove all Virtual Null Modem s devices drivers S0 Don t show messages verbose mode s1 Write messages to Windows events log S2 2004 2007 AGG Software 4 7 Virtual Null Modem 18 Show message box with messages default pa This parameter plugs in all virtual serial port devices The program reads port number from the HKEY_ LOCAL MACHINE SOFTWARE AGG Software Virtual Null Modem branch from the Ports REG_SZ key This key is created automatically by GUI application Key value example 2 7 Note The order of parameters is very important For examples if you want to get silent install of drivers then you should use the following command prompt vnullmod s0 ia FAQ and Known issues Q I want to control create and delete my virtual null
7. modems A You can do it with help of the command prompt Q I can t open a virtual serial port A If the CreateFlle function within your code uses the COM d format string as a file name then you can open COM COM9 ports only You should use COM d instead In this case you can use any virtual serial port number Q How to enumerate virtual serial ports A If you need to enumerate virtual serial ports only then you can use SetupAPI functions and search all devices for class GUID 487ECAF4 213D 4d1 7 AA07 2F91078B619D 2004 2007 AGG Software
8. a flow other than by using XON XOFF handshaking If the software is designed for using hardware flow control it seems to work with this null modem cable but on unpredictable moments data loss may occur This means that the null modem cable allows communication as long as no flow control is needed but when data speeds reach the limit the receivers can handle communication may stop immediately without an assignable reason Therefore although this null modem cable is cheap and easy to make use it with care Despite these warnings this type of null modem cable has been used successfully between Windows 95 98 ME computers with a Direct Cable Connection Null modem with partial handshaking The simple null modem cable and the null modem cable with loop back handshaking are useful 2004 2007 AGG Software Virtual Null Modem 12 but have no provisions for hardware flow control If it is absolutely necessary that hardware flow control is used the null modem with partial handshaking can be an alternative Null modem with partial handshaking Fig 3 Null modem with partial handshaking Compatibility issues This null modem cable is the best of two worlds There is the possibility of hardware flow control without being incompatible with the original way flow control was used with DTE DCE communication Let us first consider the RTS CTS flow control lines present on pins 7 and 8 As with the loop back null modem cable these s
9. cel the Add operation By default Virtual Null Modem software selects a first free ports pair Our software can emulate few typical null modem schematics You can select a null modem type from the corresponding drop down box The wires layout will be displayed on an image below the drop down box Emulated signal wires on the image are highlighted by blue color Pin numbers are showed for a DB9 connector and are displayed for your convenience only because virtual serial ports operate with signals only RTS CTS etc Quick add Hotkey Ctrl Q Right click menu Same as above but dialog window doesn t appear and Virtual Null Modem uses default values for configuring a virtual serial ports pair Configure 2004 2007 AGG Software 4 4 Virtual Null Modem 16 Hotkey Ctrl C Right click menu This opens the parameters window fig 2 for configured virtual null modem This menu item is available only if a virtual null modem had been selected in the list Delete Hotkey Ctrl X Right click menu It will delete a selected virtual null modem from your list This actions don t remove virtual null modem from your system if it had been created early You should click OK button to apply changes to your system This menu item is available only if a virtual null modem had been selected in the list Delete all Right click menu It will clear the virtual null modem s list This actions don t remove virtual null modem from y
10. ded 256 MB Free disk space Virtual Null Modem takes up about 5 MB but additional space required for log files Special login requirements You must be logged on as a user with Administrator privileges to run our software It is necessary for access certain registry keys and plug eject install virtual serial ports 2004 2007 AGG Software 5 Virtual Null Modem Microsoft Vista notes Because our software uses a kernel mode driver for creating virtual serial ports therefore 1 You need administrator privileges to run our software 2 The desktop icon of our software will contain a shield pic 1 3 Windows Vista will ask your permission to continue pic 2 A gt 1100 Virtual Noll Modem Pic 1 Desktop icon on Windows Vista O A program needs your permission to continue If you started this program continue Virtual Null Modem configaration module AGG Software User Account Control helps stop unauthorized changes to your computer Pic 2 User Account Control dialog You may disable User Account Control manager and you ll never see the dialog above Please search Google for a solution 3 2 Installation Unplug all virtual null modems if you are using Virtual Null Modem Quit of the working Virtual Null Modem before installation If any beta version was installed on your computer remove it Run an installation file Follow the instructions of the wizard during the installation process
11. eeesseeeceeenseeeeeeensneeeeeeenseeeeeesenseeeeeeensneeeeeseeseeeeenseseeeeeeeseseeeneeseeseeneneenss 3 LIMITATIONS sisina AE AAEE 4 SUPPOF EE A Installation 4 System requirements ss seennnenenensnnnennnnnnnnennennennnnnennnneennnneennneens 4 Installation RSR EEE 5 Virtual Null Modem 7 Juge Le dE 7 Typical null modem schematics sense 9 Devices UE UE 14 Syst m MENU E 16 View menti EE 17 Command line parameters sssnisnennennsnnenneennneeeneneenneneennennes 17 FAQ and KNOWN ISSUCS eege eege deed Eeer 18 2004 2007 AGG Software Virtual Null Modem 1 1 1 Introduction About software Null modem overview The purpose of a null modem cable is to permit two RS 232 DTE devices to communicate with each other without modems or other communication devices i e DCE s between them To achieve this the most obvious connection is that the TD signal of one device must be connected to the RD input of the other device and vice versa Also however many DTE devices use other RS 232 pins for out of band i e hardware flow control One of the most common schemes is for the DTE the PC to assert the RTS signal if it is ready to receive data yes it DOES sound backwards but that s how it works and for the DCE the modem to assert CTS when it is able to accept data By connecting the RTS pin of one DTE to the CTS pin of the other DTE we can simulate this handshake Also it is common convention f
12. fective product For more information to report bugs or to make suggestions please see our website at www aggsoft com or email support aggsoft com Company home page http www aggsoft com Software home page http www virtual null modem com Serial port hardware reference http www aggsoft com rs232 pinout cable License Registration and technical support License Virtual Null Modem Copyright 2001 2005 AGG Software All Rights Reserved SOFTWARE LICENSE Trial Limited Version The trial limited version of this software may be used for evaluation purposes at the user s own risk for a trial period At the end of the trial period the user must either purchase a license to continue using the software or remove it from his her system The trial limited version may be freely distributed provided the distribution package is not modified No person or company may charge a fee for the distribution of Virtual Null Modem without written permission from the copyright holder 2004 2007 AGG Software 3 Virtual Null Modem Licensed Version On payment of the appropriate license fee the user is granted a non exclusive license to use Virtual Null Modem on one computer i e a single CPU for any legal purpose at a time The registered software may not be rented or leased but may be permanently transferred if the person receiving it agrees to terms of this license If the software is an update
13. ftware will install drivers and it can take few minutes on slow computers please wait while Virtual Null Modems software adding new virtual devices This process will be accompanied by messages in the system tray like as fig 2 and fig 8 This messages will apper for each virtual serial port in the list Next time Virtual Null Modems software will not display this messages and will use drivers installed before Found New Hardware x AGG Software Virtual Null Modem 06 Fig 2 Virtual Null Modems software adds a virtual serial port 2004 2007 AGG Software 9 Virtual Null Modem i Found New Hardware Virtual Null Modem Device Fig 3 Virtual Null Modems software installs drivers After installing drivers new virtual devices will appear in the device manager see fig 4 File Action View Help x 1e A 3 Computer Hs Disk drives 2 Display adapters JA DYD CD ROM drives Floppy disk controllers HE Floppy disk drives IDE ATAJATAPI controllers 3 Keyboards Mice and other pointing devices 8 Network adapters UY Ports COM amp LPT Sound video and game controllers System devices Universal Serial Bus controllers Fig 4 Virtual Null Modems devices in the devices manager Now you can use these serial ports a serial port number showed in brackets in your software as a common hardware serial port 4 2 Typical null modem schematics Null modem withou
14. his null modem cable seven wires are present Only the ring indicator RI and carrier detect CD signal are not linked The cable is shown in the following figure 2004 2007 AGG Software 13 Virtual Null Modem Fig 4 Null modem with full handshaking Compatibility issues The null modem cable with full handshaking does not permit the older way of flow control to take place The main incompatibility is the cross connection of the RTS and CTS pins Originally these pins are used for a question answer type of flow control When the full handshaking null modem cable is used there is no request anymore The lines are purely used for telling the other side if communication is possible The main advantage of this cable is that there are two signalling lines in each direction Both the RTS and DTR outputs can be used to send flow control information to the other device This makes it possible to achieve very high communication speeds with this type of null modem cable provided that the software has been designed for it Because of the high possible connection speed this null modem cable can be used with Interlink to connect two MS DOS PC s This is the type of cable Microsoft recommends for the direct cable connection in their knowledge base article For the DB9 connector they also added a connection of DTR to CD on each connector but they didn t define this connection for the DB25 connector version and they also didn t ment
15. ignals are not connected to the other device but directly looped back on the same connector This means that RTS CTS flow control is allowed to be used in the software but it has no functional meaning Only when the software at the other side checks the CD signal at pin 1 the RTS information will reach the other device This would however be only the case in specifically developed software which uses the CD input for this purpose More important however is the cross connection of the DSR pin 6 and DTR pin 4 lines By cross connecting these lines their original function is simulated pretty well The DTR output is used to signal the other device that communication is possible This information is read on the DSR input the same input used for this purpose with modem communication Because of this cross connection the DTR output line can be used for simple flow control Incoming data is allowed when the output is set and blocked if the output is not set Software using only the RTS CTS protocol for flow control cannot take advantage of the partial handshaking null modem cable Most software however will also check the DSR line and in that case when using the null modem cable with partial handshaking the best possible hardware flow control can be achieved which is still compatible with the original use with modems Null modem with full handshaking The most expensive null modem cable is the null modem cable suitable for full handshaking In t
16. ion the CD input in the descriptive text so it is safe to leave the CD input disconnected Null modem with full handshaking 2 Same as the previous null modem layout but carrier detect CD signal are linked with the DSR signal The cable is shown in the following figure Fig 5 Null modem with full handshaking 2 2004 2007 AGG Software Virtual Null Modem 4 3 Devices menu Add new virtual null modem Ctri Quick add Ctrl Q Configure Ctrl C Delete Chr Delete all Fig 1 The devices menu Add new virtual null modem Hotkey Ctrl N Right click menu It is used to create a virtual serial ports pair After you selected this menu item a dialog window will appear fig 2 14 2004 2007 AGG Software 15 Virtual Null Modem Virtual ports First virtual serial port COM2 v C Enable interference for data transmitting ls connected with Second virtual serial port COM7 v C Enable interference for data transmitting Null modem type With full handshake 2 x Fig 2 The parameters dialog window You should select necessary port numbers from a drop down list This list displays only ports that has not been used early If you want you can add additional interference to a outgoing data flow Use a track bar for it You can specify value from 0 to 100 Click the OK button to accept your setting or the Cancel button to can
17. is linked back to the DTR output pin 4 This means that the software doesn t see the ready signal of the other device but its own The same holds for the CD input pin 1 The assumption is that if software has been written to check the DSR line to test communication availability it will probably also set the DTR output to indicate its own state This is true for at least 99 of all serial communication software This implies that at least 99 of all serial communication software is capable of faking its own DSR check with this null modem cable The same trick is used with the CTS input In the original use RTS is set and then CTS is checked before starting the communication By setting the RTS output pin 7 the CTS input on the same connector pin 8 is receiving clearance immediately There is no possibility of a software hang up because of dangling RTS requests Other issues to consider The null modem cable with loop back handshaking is often advised as the best low cost available null modem cable But is it really so good The simple null modem cable without handshaking has the disadvantage that it does not permit proper written software to communicate with it Software which is aware of the lack of handshaking signals can however use it without problems The null modem cable with loop back handshaking can be used with more software but it has no functional enhancements over the simple cable There is no way both devices can control dat
18. labeled 1 Menu bar Menus are described in the Menus section of this help file 2 Virtual Null Modems list contains a list with virtual null modems created 3 Auto start box allows to configure VNM start with Windows If this box is checked next time you boot no virtual serial ports will be created Otherwise you should start VNM application and click the OK button Virtual Null Modem 2 0 1 5 Jo x Devices System View Help ln S COM12 COM13 o COM14 COM15 M COM2 COM3 M COM4 COMS5 M COME COM 3 2 C Enable virtual null modems every Windows start up Fig 1 The main program window The menus of Virtual Null Modem are located on the menu bar The sub menus of the main menu are Devices System View and Help Each item in these menus is described in this section below Some menu functions are also activated by pressing combinations of keys on the keyboard called Hotkeys in this Help file Another way to access some edit menu functions is to click the right button of the mouse See the help paragraphs on each function for more information Hotkeys are described thus Ctrl N means that the user holds the Ctrl key down while simultaneously pressing the N key The appropriate keyboard shortcuts and toolbar buttons are shown with each menu item After adding serial port pairs you should click the OK button to apply all changes If it s first time when you had added serial port pairs then Virtual Null Modems so
19. o install Fig 3 Vista popup After you install the program configure the program step by step as described below 4 Virtual Null Modem 4 1 Introduction Highlights No reboot required Creating installing and removing of virtual serial ports occurs at real time You can create any number of virtual serial ports pairs Any other hardware or virtual serial ports are not used or occupied You even can have no serial ports in your system Other applications will never see the difference between real serial port and virtual serial ports created by Virtual Null Modem software The link between two virtual serial ports is faster then real null modem cable connection and depends on your computer system speed e The virtual link is much more reliable than common physical link Virtual Null Modem uses kernel driver technology and supports WDM WMI Power Management PNP etc Virtual Null Modem software has a simple menu driven step by step set up Programming is not required to configure the software to configure virtual serial ports and virtual serial ports pairs If you are software developer then you can configure each port to sumulate a real world data exchange with errors in data Once the program is launched the main program window is opened fig 1 It is the configuration 2004 2007 AGG Software Virtual Null Modem 8 window This image below shows the Virtual Null Modem screen with its various parts
20. or many DTE devices to assert the DTR signal when they are powered on and for many DCE devices to assert the DSR signal when they are powered on and to assert the CD signal when they are connected By connecting the DTR signal of one DTE to both the CD and DSR inputs of the other DTE and vice versa we are able to trick each DTE into thinking that it is connected to a DCE that is powered up and online Software overview Virtual Null Modem VNM is an utility which purpose is to emulate one or more RS232 serial ports connected via virtual null modem cable Otherwise you can create any number of pure virtual serial ports in your system COM10 COM11 COM255 etc that will be connected to each other via virtual null modem cable If you have two applications you want to connect to each other using serial ports you need a null modem A null modem is bascially a cable to connect two serial ports to each other Normally you need two computers or two physical ports on one computer to achive this Using Virtual Null Modem software you can emulate the null modem and run the two applications on the same computer without any additional hardware Example You can create two virtual serial ports COM10 and COM12 and connect two different applications to them Everything that application 1 will send to COM10 will be received by application 2 at COM12 and all that application 2 sends to COM12 will be received by application 1 at COM10 Features
21. our system if it had been created early You should click OK button to apply changes to your system System menu Plug in all virtual null modems Reinitialize all virtual null modems Unplug all vertual null modems Reinstall all drivers Fig 1 The System menu Plug in all virtual null modems Choose System gt Plug in all virtual null modems to insert new virtual null modems to your system This command can be useful if you created new virtual null modem and want to apply changes immediale Reinitialize all virtual null modems Choose System gt Reinitialize all virtual null modems to apply all changes to your system This command can be useful if you changes your configuration and want to apply changes immediale This command is mostly identical to the click of the OK button but without closing application Unplug all virtual null modems Choose System gt Unplug all virtual null modems to remove all virtual null modems from your system but nor from the list in the configuration window 2004 2007 AGG Software 17 Virtual Null Modem 4 5 4 6 Reinstall drivers Choose System gt Reinstall drivers to try to install all virtual null modems drivers to your system View menu Icons There are four ways to display the icons in the virtual null modem s views Big icon Small icon List and Table Arrange Icons The way icons are arranged can help identify Command line parameters p
22. t handshaking How to use the handshaking lines in a null modem configuration The simplest way is to don t use them at all In that situation only the data lines and signal ground are cross connected in the null modem communication cable All other pins have no connection An example of such a null 2004 2007 AGG Software Virtual Null Modem 10 modem cable without handshaking can be seen in the figure below Fig 1 Null modem without handshaking Compatibility issues If you read about null modems this three wire null modem cable is often talked about Yes it is simple but can we use it in all circumstances There is a problem if either of the two devices checks the DSR or CD inputs These signals normally define the ability of the other side to communicate As they are not connected their signal level will never go high This might cause a problem The same holds for the RTS CTS handshaking sequence If the software on both sides is well structured the RTS output is set high and then a waiting cycle is started until a ready signal is received on the CTS line This causes the software to hang because no physical connection is present to either CTS line to make this possible The only type of communication which is allowed on such a null modem line is data only traffic on the cross connected RxD TxD lines This does however not mean that this null modem cable is useless Communication links like present in the Nor
23. ton Commander program can use this null modem cable This null modem cable can also be used when communicating with devices which do not have modem control signals like electronic measuring equipment etc As you can imagine with this simple null modem cable no hardware flow control can be implemented The only way to perform flow control is with software flow control using the XOFF and XON characters Null modem with loop back handshaking The simple null modem cable without handshaking shows incompatibilities with common software The main problem with this cable is that there is a possibility for the software to hang if it checks the modem signal lines in a proper way l e with this null modem cable good written programs will perform worse than badly written programs To overcome this problem and still be able to use a cheap null modem communication cable with only three lines in it a fake null modem cable layout has been defined The null modem cable with loop back handshaking resulted from this 2004 2007 AGG Software 11 Virtual Null Modem Fig 2 Null modem with loop back handshaking The main purpose of this null modem cable is to let well defined software think there is handshaking available with a null modem cable which has no provisions for it Compatibility issues Consider first the DSR signal pin 6 This input indicates that the other side is ready to start communicating In the layout the line
Download Pdf Manuals
Related Search