Small embedded GSM modem?

Have a look at Siemens modules.

Maciek.

I'm using the Siemens MC55, they are very small.

Leon

Yes, I was considering that. Do you know a reputable site/dealer that sells in the US?

Thanks

A

TDC distributes them here in the UK. Siemens should have US distributors on their web site.

Leon

I have a few questions about the MC55/56 and I apologize if they sound too naive:

- How would you go about connecting it to another board? Directly or using a ribbn cable to the hirose 50 pin connector?

- Do you use an antenna with it, and if yes, which one so it remains a small package?

- Does it have a Sim card receptacle or is that an add on?

Thanks in advance.

A

The Hirose 50 way connector (0.5 mm spacing leads) has to go on a PCB; it's one of the smallest board-board connectors made, BTW. I've designed a prototyping PCB for it, with a SIM card socket and a 10 way connector to the MCU board on it.

I've got an awkward short between two pads on the 50 way connector, right under the plastic, I can just see it with a microscope. That's probably why I can't get the thing working. 8-(

The antenna is external, TDC supplies an adapter cable which connects the tiny coax socket to an SMA connector.

Leon

Thank you for the prompt reply. Which MCU are using with it? What I will be doing is to try to send images to a server over EDGE or GPRS. I am trying not to make a mistake and buy components that end up not working together.

Any suggestions/pointers will definitely help.

Best,

A

PIC 16F88. I'll be using a 16F690 on the production version as I will need some more I/O.

Leon

Thank you for the prompt reply. Which MCU are using with it? What I will be doing is to try to send images to a server over EDGE or GPRS. I am trying not to make a mistake and buy components that end up not working together.

Any suggestions/pointers will definitely help.

Best,

A

Thank you for the prompt reply. Which MCU are using with it? What I will be doing is to try to send images to a server over EDGE or GPRS. I am trying not to make a mistake and buy components that end up not working together.

Any suggestions/pointers will definitely help.

Best,

A

If you want to use GPRS/EDGE, "any" MCU will do as long as it will have PPP/IP stack, preferably fast serial port or USB Host. Another approach you could look into is choose a module with built in IP stack (accessed by AT commands). That way no PPP/IP required for MCU. I think MC75 will do the job in that case. For one of my projects I've used Zilog's eZ80 and it works pretty well.

Maciek.

Apologies for the multiple posts.. browser hung....

Leon, thank you for all the valuable info, but i just found out that the evaluation kit for the MC55 is expensive. Can one do without it or is it a must have?

A

Maciek, Thank you for your input. Yes, the reason I chose the MC55 (also has a built in TCP/IP stack) is because it is small in size , an important requirement. I am sure any MCU will work. I am pondering what is the best way to go since I need to do image compression from an image sensor before I send over GPRS/EDGE.

You just need one of the modules (68 GBP), and a PCB for it, like the one I described.

Leon

The MC55 has a TCP/IP stack.

Leon

I'd say no. Just a matter of hooking up serial lines and 2 control wires for modem start up / power down (if IO is at premium you can even get away without them, although they are useful) and SIM card. If you want "higher level integration" then that offered by Siemens module itself, you can look at falcom

embedded modules. Internally they have MC55 (at least some of them do). Falcom also offers terminals based on MC55 - in case you want to take it apart and look at the signals (as for possibility of hooking up to them that's another question ;-)

Just keep in mind that MC55/56 does not have EDGE, only GPRS class 10, thus upload speed will be 2 uplink slots at max (with local networks the best transfer I was able to get was about 2-3kbps with MC39i - also GPRS class 10). If you want EDGE, you'll need to go with MC75.

Maciek.

Check modules from sonyericson

many models to choose from. Regards, Viron.

amerdsp wrote: