adammck / rubygsm

Ruby interface to AT-compatible GSM modems

RubyGSM is a Ruby library which uses ruby-serialport to provide a nifty interface to send and receive SMS messages via a GSM modem.

Sample Usage¶ ↑

class ReverseApp
    def initialize(gsm)
        gsm.receive(method(:incoming))
        @gsm = gsm
    end

    def incoming(from, datetime, message)
        @gsm.send(from, message.reverse)
    end
end

gsm = Gsm::Modem.new("/dev/tty.usbserial")
ReverseApp.new(gsm)

If you just want to send sms

gsm = Gsm::Modem.new("/dev/tty.usbserial")
msg = Gsm::Outgoing.new(gsm, "[phone]", "Oh hai")
msg.send!

Installing¶ ↑

RubyGSM is distributed via GitHub, which you must add as a gem source before installing:

$ sudo gem sources -a http://gems.github.com

The library depends upon ruby-serialport, which is currently maintained on GitHub by Toholio. This library is included as a Gem dependancy, so to install both:

$ sudo gem install adammck-rubygsm

For Debian/Ubuntu users…¶ ↑

The ruby-serialport library is available in the APT repository as a binary package, which is substatially less hassle to install than the Gem, for those who don’t have a compiler installed (I prefer not to, on production servers). To install the package via apt, and ignore the Gem dependancy:

$ sudo apt-get install libserialport-ruby
$ sudo gem install --ignore-dependencies adammck-rubygsm

Building gem¶ ↑

$ gem build rubygsm.gemspec

Known issues¶ ↑

There is a known issue when you try to send message to shortcode. Enble :debug to see problem.

Devices Tested¶ ↑

• Multitech MTCBA

• Wavecom M1306B

rubygsm's Issues

Infinite ack (+CNMA) and reboot (+CFUN) loop.

Let me start by saying thanks for making this library available. Secondly I realise that you haven't touched the code in a long time, so I'm not expecting you to look into this, but maybe you have an idea of how to fix it that would be consistent.

I ran into an issues around retries. I received a message which the library then attempts to ack with a +CNMA.
The modem responds with +CMS ERROR 340, which is "No +CNMA acknowledgement expected". The command is retried 5 times, all of which fail. The device is then reset with a +CFUN command, which succeeds, and the command is retried. The code then gets stuck in an infinite loop of try and fail command, reset device.

This problem will always be triggered with a command that fails legitimately (ie. it will always fail), and a modem that always resets successfully.

I see a few options:

1. A simple workaround of making @reset_on_failure false. Based on your comments it does seem like the reset is a very useful feature, so I don't really want to change that.
2. Change parse_incoming_sms! to use try_command for +CNMA. Any errors rising from that command are ignored anyway (they are just logged). I like this, but it still doesn't solve the root problem.
3. Only reboot once in command. eg. Try 5 times, reboot, try 5 times again, propgate error.

I like the idea of doing both 2 and 3, so I'll throw together a patch, unless you have a better idea.

Thanks,
Liehann

Could this be used to make an http post using the AT commands for http requests?

I know that this library creates a connection to the GSM modem and provides the ability to send SMS messages. Could it be used to send AT commands to facilitate an HTTP post?

I am trying to find an abstraction layer on top of the AT command set to provide a simple HTTP client.