SMS libraries (for GSM phones)

Here you will find ready-to-use libraries for working with SMS messages.

You can use this software free of charge, but at your own risk.

Libraries overview

• GSM Communication Library (GSMComm)
• GSMComm Frequently Asked Questions (FAQ)

GSM Communication Library (GSMComm)

GSMComm is my own written communication library for GSM phones, mainly for performing SMS-related tasks.
Other developers can re-use this library for their own projects.

Features:

• Manage SMS messages: Send, read, delete, store, import and export messages, get memory status, get/set SMSC
• Manage the phonebook: Create, find, delete, read, import and export phonebook entries, get memory status
• Manage the phone: Read general info, reset configuration, enter PIN
• Supports notifications about new messages as well as forwarding them directly to the application
• Detect phone connection/disconnection
• Other SMS message variants also possible, such as alerts and notifications
• Support for Smart Messaging to create concatenated text messages and operator logo messages
• Includes a debug mode to assist in troubleshooting
• Support for GSM 7-bit default alphabet and Unicode for the message text
• Supports some operator functions
• Remoting support for sending SMS messages

System Requirements:

• Windows 2000, XP, Server 2003 or Vista
• .NET Framework 1.1 (+SP1) or .NET Framework 2.0 (32-bit version, 64-bit version).
• A GSM phone or modem that supports AT commands

Also included:

• Reference documentation in XML and CHM (HTML Help) formats
• Source code samples

Download the development package here:

Download
	Version 1.11 for the .NET Framework 1.1 GSMComm_v1.11_net1.1.msi
	Version 1.11 for the .NET Framework 2.0 (32-bit) GSMComm_v1.11_net2.0_x86.msi
	Version 1.11 for the .NET Framework 2.0 (64-bit) GSMComm_v1.11_net2.0_x64.msi

What's new in Version 1.11?

• .NET 2.0 version only: Added a 64-bit installer.
• .NET 2.0 version only: Fixed error that 8-bit characters do not transmit correctly between phone and application. The communication is now encoded with code page 1252 (Windows). Previously 7-Bit ASCII has been used, which truncated the 8th bit. The .NET 1.1 version of GSMComm already uses CP 1252.
• .NET 2.0 version only: Documentation has now VS2005 MSDN style (using one of the last NDoc 2.0 alpha versions to keep content consistent).
• The first call to Open() now prints out the GSMComm version in the log.
• Selecting the active read or write storage now works on phones that return an alternative response that also contains the names of the active storages. This fixes also calls to methods that switch the storage before executing the actual command, like ReadMessages().
• Fixed an error that occurs when getting subscriber numbers and logging is enabled at the same time.
• Getting the subscriber numbers now returns also records that do not actually contain a number. Previously, such records were ignored.
• Fixed a parser error in situations where only the first character of an unsolicited message was received.
• Enhanced a few error messages.
• Enabling message notifications and routing is now possible on phones that only support the "ForwardAlways" indication mode.

Troubleshooting

If you encounter issues using GSMComm, use the following hints to investigate them:

• Look at the included documentation to know what you can generally do and for details to every command.
• Look at the included sample source code for examples how to use the library.
• Read the FAQs on this website to find answers to common questions.
• If you suspect a communication problem, try different communication settings or if that doesn't work, test the connection using a different communication program, like HyperTerminal, which is included in Windows.
• If your phone seems to be in an strange state, try resetting its configuration.
• If the phone or GSMComm doesn't work like you expect it, generate a debug trace to analyze the phone's behaviour and how GSMComm interprets certain responses.
• If you have multiple devices, check whether the problem is only restricted to one specific device or a specific model.
• If the issue is of a general nature, ask a friend, someone in a forum or your favourite web search engine.

GSMComm Frequently Asked Questions (FAQ)

• Q: The phone/modem locks up after sending a lot of messages in succession, or returns errors like error code 301 (SMS service of phone reserved).

  A: This is probably a timing issue. The messages are sent too fast and the phone/modem can't catch up with it. Try a delay of one or more seconds before sending the next message. If you're using version 1.9 or higher, try the SMS batch mode if your phone and network support it.

• Q: I have a .NET Framework 1.0, but the GSMComm setup doesn't work because it wants a higher .NET version. Do you have a solution?

  A: Yes, install a higher version of the .NET Framework, quickly! You can keep your old version as long as you need it, because the framework supports side-by-side installation.

• Q: Does GSMComm work with Unicode messages?

  A: Yes, some Unicode support is built in since version 1.61.

  GSMComm can create, send and decode Unicode text messages. For creating Unicode messages, just be sure to set the correct DataCodingScheme before setting the UserDataText in the SmsSubmit object and it's all right. For Smart Messaging (concatenated SMS messages) only creating and sending of Unicode messages is supported, decoding does not work.

• Q: Is it possible to get incoming messages as an undecoded PDU string?

  A: Yes, use the GsmCommMain.ReadRawMessages method for that.

• Q: How can I send long (concatenated) text messages?

  A: GSMComm implements a part of the "Smart Messaging" standard defined by Nokia. The methods for it are implemented in the GsmComm.PduConverter.SmartMessaging.SmartMessageFactory class. It supports creating long messages for standard SMS text as well as for Unicode messages (Built-in Unicode conversion starts with Version 1.61).

  Mobile phones that don't support Smart Messaging but use some other SMS-enhancing standard, like EMS, may not be able to send or decode such messages properly.

• Q: I get the error "No phone connected" and I have verified that the connection works properly using a communication program like HyperTerminal.

  A: This is probably because of communication timeouts. The phone/modem does not reply within the time waited by GSMComm. Try to use higher values for the timeout parameter in the constructor of the GsmCommMain or GsmPhone object. The default communication timeout does not necessarily work for all devices, some are slower, some are faster. This also depends on the baudrate used.

• Q: Will GSMComm support CDMA at some time?

  A: No. The name GSMComm implies working for GSM networks and not for others. But besides the name, I don't do anything with CDMA and currently do not intend to work myself into CDMA.

• Q: Do you recommend a specific phone/modem?

  A: No. For most of the tests, Nokia phones have been used, but it's not restricted to them. As long as the phone/modem meets GSMComm's requirements and supports the features you need, you can use whatever model you want.

• Q: Is there a limit on how many SMS messages can be sent, e.g. per day?

  A: GSMComm does not restrict the number of messages in any way. However, the network provider may limit your possibilities, for example if you use a prepaid account.

• Q: Can I use GSMComm for multiple phones/modems?

  A: Yes, use multiple instances of the communication classes for that. If you want asynchronous processing, you have to handle that yourself.

• Q: I think GSMComm didn't properly pick up a response from the phone/modem. Can I check this somewhere?

  A: Yes. You can use GSMComm's logging mechanism (basically the LoglineAdded event) to find out what was sent to the phone, what responses were received and often also how GSMComm interpreted the response. This may give you a hint about where the fault came from.

• Q: What does the "Phone reports generic communication error or syntax error." error really mean?

  A: This is how GSMComm interprets the ERROR response if something isn't right. Many issues can be the cause, including:

  • There is a communication problem on the hardware level.
  • The syntax of a command is invalid. Example: The phone requires 3 parameters of a specific command but got only 2.
  • The phone is in a state where the command is not valid. Example: Trying to send SMS messages while the phone waits for a PIN code to be entered.
  • The command is not supported at all. Example: Some phones don't allow you to read contacts or SMS messages.