DISCLAIMER:
THIS CONTENT IS PROVIDED TO INTERESTED PEOPLE "AS IS" FOR NON COMERCIAL
PURPOSE ONLY. UNDER  NO CIRCUMSTANCES I AM RESPONSIBLE  FOR ANY DAMAGES 
TO YOUR MOBILE, PC OR OTHER  EQUIPMENT. THIS  DEVICE AND SOFTWARE WHERE 
TESTED  UNDER DIFFERENT CONDITIONS  AND  UNTIL  NOW THEY WORK   WITHOUT
PROBLEMS.

The add on's to SMS-Link presented here are written by Richard Prinz and allows you to enhance SMS-Link in various ways.

1. Enhanced Windows 32 Client
2. Queue Server
3. WEB Interface to the Queue Server
4. The Cable

1. Enhanced Windows 32 Client

You can for example send SMS messages right from your desktop via TCP/IP either with a graphical user interface or via the commandline. This is especially usefull if you would like to send SMS messages from batch jobs or from your SNMP management console. (indeed this was the main reason for developing this add on's. Before this I used PageIt (a Pager / SMS software using the TAP protocol also available on this site).

To install it on your PC just download it and run the installer.


Image 1: Windows SMS-Link Client with activated debugging mode.

To see how to run the client from the command line just click the help menu item within the client. This will bring up the following window:


Image 2: Command line parameters of the windows client.

The client also allows you to send SMS messages to more than one recipient. Just separate the mobile nubers with a ','. It Is also possible to define user groups. Whenever you enter a recipients number which starts with a '@' this defines the name of a textfile where all recipient numbers are listes one at a line. To edit this text files the label in front of the field turns from back to blue. By double cklicking it notepad starts allowing you to edit the group files contents.


Image 3: Group file


 

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2. Queue Server

I also added a so called queue server which allows you to send SMS messages without waiting til they are delivered - optionally you can define an email address to which a delivery report will be sent. This server is a simple perl script which is invoked by inetd. To install the queueserver first download it and then follow this steps:
 
1. install SMS-Link as described in the SMS-Link documentation. Ensure that SMS-Link is working correct before proceeding
    
2. now install the add on's to the same directory where you have installed SMS-Link (eg. /usr/local/bin)
    
3. modify the paths for the gsmaccess, gsmcounters files and the queuedirectory path in the sms_qserv.pl file (just follow the comments)
    
4. setup a gsmcounters file (usually in the same directory as the other gsm config files eg. /etc). The syntax of this file is very simple. It consists of 3 fields on a line separated by ':' with the first field the user name, next the current available SMS messages left to send (when 0 is reached this user is unable to send a SMS) and the third field the maximum allowed SMS messages this user can send. The letter 'U' in the second field means: this user can send unlimited messages. The letter 'D' in the third field means: use the default settings for this user specified by the default entry. Every time a user sends a SMS the second field is decremented. After reaching 0 the user is unable to send a SMS. Running the counters.pl script from a crontab lets say every 1st of the month will set all counters back to the allowed maximums for each user. If a user is not found in the counters file it is prohibited. To temporary disable a user enter 0 in the 2nd and 3rd field.

   Example gsmcounters file

   default:5:5
   testuser:3:D
   itsme:U:D
   johndoe:0:10
   

5. next modify the /etc/services the following way:

   sms             6701/tcp        # SMS Link Server
   smsq            18920/tcp       # SMS queue server
   

6. add this line to your /etc/inetd.conf

   smsq    stream  tcp     nowait  root    /usr/sbin/tcpd     /usr/local/bin/sms_qserv.pl
   

   NOTE: depending on the used inetd the syntax of the inetd.conf may be different or even the inetd.conf does not exist. Consult your system documentation on how to start server programs for incoming tcp connections
    
7. be sure to include all allowed client ip addresses in the gsmaccess file (eg. y:127.0.0.1/32)
    
8. now test the queue server the following way:

   telnet name-of-queue-server 18920

   You sould see something like this:

   Trying 127.0.0.1...
   Connected to localhost.
   Escape character is '^]'.
   
   SMS-Link QueueServer V1.5
   (c) Richard.Prinz@MIN.at 2003
   Connect from localhost (127.0.0.1:1621)
   
   SMS>
   

   If you see the queue server welcome message you are nearly done. Using the queue server is fairly easy. You either could use the Windows 32 Client also described on this page or you could use simple telnet. At the first prompt you enter the user name (see gsmcounters), at the next prompt you enter the destination gsm number, at the next you write your message and at the 4th prompt you can enter an email address to which a delivery report will be sent after your message has been delivered (or not). You can leave this empty if you want. If so no report is sent. At the next prompt enter a single '.' as the first character. This leaves the server.
    
9. When you have testted your queue server as described under point 8 you will find a file with the extension .smsq in your queuedirectory. This file will be read by squeue.pl which is started by cron automaticaly every minute. To do this enter the following line into your crontab:

   */1 * * * *     /usr/local/bin/squeue.pl 2&>1 > /dev/nul
   

   Every time squeue.pl runs it reads the files in the queuedirectory and sends it using sendsms.

 

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3. WEB Interface to the Queue Server

Based on the samples from the original SMS-Link archive I developed a comfortable Web interface embedded inside the UebImiau Webmail (found at http://www.uebimiau.org/). This gives you a integrated sollution for sending emails and sms's via the Web. Features include:
 
• Completely integrated into WebMail
• Extension to the WebMail Addressbook to store the mobile number for a contact an pick it from there when sending
• capable of using either the direct or queued SMS-Link mode
• Customizable OK,ERROR and STATUS web responses
• when using queue mode an email is sent back to the sender with the state of the SMS

 
Image 4: WebMail Main Screen


Image 5: SMS Screen


 

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4. The Cable

Just in case you don't use a GSM module but an ordinary mobile phone you sooner or later come to the point finding that using normal available datacables to connect the phone to the pc have some big drawbacks. First you need a cable for every different brand of mobile (and these cables are not cheep), then you normaly can not connect the datacable AND the power supply to the mobile the same time. So that's why I developed this super simple interface.

It works with nearly every type of phone, allows the use of the power supply when the datacable is connected and it can be powered either from the PC serial port via the DTR / RTS pins (the software used must support this - the DTR and/or RTS pins must be set by the software - also some PC's serial ports does not supply enough power via this pins - especially laptops! Replacing the Voltage regulator IC2 (78L05) with this circuit may also help to solve this), the phone (ensure that the phone has a BAT pin for powering external hardware) or via an external power supply. All these options can be selected via jumper JP1.

All inputs and outputs to the interface are done using RJ45 plugs. So if you switch from one mobile to another one with a different connector you just have to change the phone cable - the interface stays the same.

Also some phone power supplies needs to talk to the phone to regulate the charging voltage. Up to two control lines can be "tunneled" throu the interface from the powersupply to the phone. The converter itself is not very magic. It's just a standard MAX232 level converter. Replacing the MAX232 with a MAX3232 and also replacing the Elkos with 100nF capacitors 3V operation is possible.

Some phones require a pull up resistor in their RX line (eg. SIEMENS phones) this can be accomplished with a jumper JP2.

Here you can see some pictures of the finished cable as well as the schematic and also a PCB for building it.


Image 7: The Schematic

Image 8: The PCB foil		Image 9: and in real
Image 10: Component layout		Image 11: and finished


Image 12: Complete assembly of cable and phone

You can download a PDF File with the schematic and the PCB here.
If you dont have the Adobe Acrobat Reader installed on your machine you can find it here

Last modified: 13.05.2003
Any questions? Just mail me: Richard.Prinz@min.at