For those who want to take it to the next level we now have a 3G Cellular Modem breakout! The FONA 3G has better coverage, GSM backwards-compatibility and even sports a built-in GPS module for geolocation & asset tracking. This all-in-one cellular phone module with that lets you add location-tracking, voice, text, SMS and data to your project in a single breakout.

This module measure only 1.75"x1.6" but packs a surprising amount of technology into it's little frame. At the heart is a powerfull GSM cellular module (we use the latest SIM5320) with integrated GPS. This module can do just about everything

• Quad-band 850MHz GSM, 900MHz EGSM, 1800MHz DCS, 1900MHz PCs - connect onto any global GSM network with any 2G SIM.
• American Version dual-band UMTS/HSDPA 850/1900MHz WCDMA + HSDPA
• European Version dual-band UMTS/HSDPA 900/2100MHz WCDMA + HSDPA
• Fully-integrated GPS (Qualcomm PM8015 GPS) that can be controlled and query over the same serial port
• Make and receive voice calls using a headset or an external 8Ω speaker + electret microphone
• Send and receive SMS messages
• Send and receive GPRS data (TCP/IP, HTTP, etc.)
• AT command interface can be used with 300, 600, 1200, 4800, 9600, 19200, 39400, 57600, 115200, 230K, 461K, 961K, 3.2M, 3.7M and 4.0Mbps
• Native USB support - plug it into a computer and you'll get serial ports for AT commands, GPS NMEA as well as a modem (note we've only tried out the AT&NMEA ports on Windows)

Here's the GPS specifications:

• 16 acquisition channels
• GPS L1 C/A code
• Sensitivity
  Tracking: -157 dBm
  Cold starts : -144 dBm
• Time-To-First-Fix
  Cold starts: 100s (typ.)
  Hot starts: 1s (typ.)
• Accuracy: approx 2.5 meters

We strongly recommend using an active antenna with the GPS, while we could get a fix with a passive antenna it took a long time.

Please note! We've had a lot of requests for a 3G cell module and we're happy to oblige but this module has many small differences between it and the FONA 800 and 808, so it is not a drop-in replacement! In particular the data functionality is not as easy to use. We are adapting our FONA library to support the 3G chipset and right now we have SMS, calling, and basic functionality working but it will be a while until we get full GPRS TCP/IP and HTTP support. Also, the GPS is not as fast and low-power as the one on the FONA 808. We recommend this module for people who are able to handle a more advanced experience. Beginners will like our FONA 80x series more.

Sounds great, right? So we kitted out this fine module onto a little breakout with all the extras you need to make your next project shine

• Onboard LiPoly battery charging circuitry so you can take your project on the go. Use any 500mAh+ LiPoly or LiIon battery and recharge over the MicroUSB when necessary. Two LEDs let you know when its charging and done
• Standard 4-pole TRRS headphone jack. Use any 'Android' or 'iPhone'-compatible headset with mic
• Breakouts for external 8Ω speaker and electret mic if you don't want to use a headphone
• Level shifting circuitry so you can run it with 2.8V to 5V logic.
• uFL connections for external antennas
• Indicator LEDs for power and network connectivity
• Standard SIM slides into the back

On its own, this module can't do anything. It requires a microcontroller to drive it! We suggest and use an Arduino but any 3-5V microcontroller with a UART can send and receive commands over the RX/TX pins.

You will also need some required & recommended accessories to make FONA 3G work. These are not included!

• SIM Card! A 2G or 3G Mini SIM card is required to do anything on the cellular network.
• Lipoly Battery - 500mAh or larger! This 1200mAh will work great.
• MicroUSB cable for charging the battery and communicating with the module over USB
• External uFL GSM Antenna - this slim one works great.
• (or, if you want to us an SMA antenna - a uFL to SMA adapter cable.)
• External Active GPS Antenna (needs a uFL to SMA adapter too) - like this one!
• TRRS 4-Pole Headset - Not required but it'll be tough to make a phone call without it. Any 'iPhone' or 'Android' compatible (but not iPhone original) should work. We tried about 10 different ones, and basically the more expensive once are more comfortable and louder but our official iPhone headset mic did not work.

In order to use the phone parts of FONA you will need a SIM card. Luckily, there's a phone store in every town in America! You can get a pre-paid or post-paid SIM but we kinda like the pre-paid kind.

A 2G or 3G Mini SIM card is required to use the module. Nearly any cell phone shop can sell you a SIM card. Luckily, every SIM we've seen is 2G or 3G so you are good to go!

The FONA 800 and 808's use a 2G SIM only. Make sure you're using a SIM that can do 2G. In the USA, that's a T-Mobile or reseller

The FONA 3G can use either 2G or 3G. These modules will only work with AT&T in 3G mode. Unfortunately, AT&T is deprecating its 2G network, so you will only be able to use this module in 3G mode with AT&T.  If you want to use it with 2G, use T-Mobile

MicroSIMs won't fit - so make sure its a "Mini" SIM. Sometimes these are just called plain "SIM" cards since the huge-size SIMs are rarely used. Mini SIMs are 1" x 0.6" / 25mm x 15mm. these are by far the most common size.

Adafruit now sells the TING SIM card, a 2G+3G SIM that works great with all FONAs, and has a great billing system as well, where you only pay what you use!

Some suggestions from FONA users!

• I've had good luck using the FONA with a SIM from Walmart. Their 'Walmart Family Mobile' is a T-mobile reseller and you can pick up the SIM starter in store pretty easily . The service isn't the cheapest, it's $25 for the SIM and $30/month for unlimited talk+text or $40/month for unlimited talk+text+data but there's no contract as its all prepaid -tdicola
• Just want to let the Adafruit team know that it is possible to get pre-paided minutes on T-Mobile and its a pretty good deal. I was paying $100 for 1000 minutes (10c a minute 20 a sms) over the course of the year. For me it in my usage came out to about $8 a month. Have found this is something that you have to ask for at the store. No evidence in advertising or website -Paul B.
• Telna has a good deal you may want to point people to for FONA. I used them for a previous GSM project and they worked great. $20 per year, includes 1000 free txt messages and a bunch of other nice features. I had a lot more issues with T-Mobile (Their cards go inactive if not used in a month and you have to call to reactivate) -Tyler C.
• I pay 2 EUR (a bit less than $3 USD) for 2 hours, unlimited SMS and 50Mb of Data at http://mobile.free.fr/ -KTOWN
• There are specialty "machine 2 machine" SIM sellers that have plans that are tuned for the short bursts of usage used by these kinds of modules. Check out these guys for example, you can choose data, voice/sms or a combination for a pretty low price!

There's a lot packed into the FONA 3G lets go thru all the pins, buttons and indicators and what they do

Connectors

There's three external connectors along the left side, from the top, a mini JST 2-pin, a microUSB and a headphone jack.

• JST 2-pin - this is the battery input connector. It works with any of our Lipoly batteries but since the charge rate is 500mA (and the cellular module can spike high current draw!) we suggest our 500mAh or 1200mAh batteries. You can also connect a JST cable here if you have other plans.
• MicroUSB connector - this is the LiPoly/LiIon battery charging port. The SIM808 has a USB interface but its ONLY for reprogramming the module with an expensive and unavailable IDE. So charge only! The charge rate is 500mA max.
• Headset jack - this is a 'standard' TRRS 3.5mm phone headset jack with stereo earphone and mono microphone. Any 'iPhone' or 'Android' compatible (but not iPhone original) should work. We tried about 10 different ones, and basically the more expensive once are more comfortable and louder but our official iPhone headset mic did not work for unknown reasons. Sleeve is Mic+, first ring is ground, then the second ring and tip are for stereo audio. The module does not have stereo out so we just tied both together.

Antenna ports

Up top is the place where you can plug in your GSM antenna. An antenna is required to use the module for any kind of voice or data communications as well as some SIM commands!

You can either use a uFL GSM antenna like this, or use a uFL to SMA adapter and then an SMA antenna

On the left is a GPS antenna port. While you can connect a passive GPS antenna directly, we've found the performance is lacking. We recommend shorting the solder jumper labeled 'bias' and connecting an Active GPS antenna instead, such as the one we stock in the adafruit shop

SIM Connector (on Back)

A 2G or 3G Mini SIM card is required to use the module. Nearly any cell phone shop can sell you a SIM card. For USA customers, we have a known-working TING SIM card which has a great billing system and works very well!

MicroSIMs won't fit - so make sure its a "Mini" SIM. Mini SIMs are 1" x 0.6" / 25mm x 15mm. These are by far the most common size.

Most cards come with a voice and/or data plan. If you want to make phone calls and SMS's you'll need a voice plan. If you want to transmit data like fetching a webpage, you'll need a data plan.

Bottom Breakouts

The most important pins are broken out at the bottom of the board. Not all of these are required, but they are all hella useful

These are in rough order of most important (not in linear order like we usually do)

These pins are all 3-5V input safe and if they are an output, the logic level is whatever Vio is set to.

• Vio - THIS IS THE MOST IMPORTANT PIN! This is the pin that you MUST drive with an external voltage from 3V-5V to set the logic level converter. The converter also buffers the indicator LEDs so NOTHING will appear to work unless this pin is powered! You should set the voltage to whatever voltage your microcontroller uses for logic. A 5V micro (like Arduino) should have it be 5V, a 3V logic micro should set it to 3V.
• Key - This is also a super important pin (but not as important as Vio). This is the power on/off indicator. Its also tied to the button in the top left. Tie this pin to ground for 3 to 5 seconds to turn the module on or off. It's not a level signal so it isn't like "low is off, high is on" - instead you must pulse it for ~5 seconds to turn off/on. The module comes by default off. Tie this permanently to ground if you never want your micro to turn off the FONA for power saving
• 5V - this is the USB 5V from the microUSB connector when its in and powered. Good if you need to know when the microUSB is plugged in and/or want to recharge the battery from an external plug.
• PS - this is the Power Status pin. It is low when the module is off and high when the module has power. If you're using the Key button or pin, you can monitor this pad to see when the module's booted up. This is tied to the Pwr LED too.
• NS - this is the Network Status pin. It lights up/blinks to signal the current status of the module. This is also tied to the Net LED so for more detail see the LEDs section below.
• Reset - this is module hard reset pin. By default it has a high pull-up (module not in reset). If you absolutely got the module in a bad space, toggle this pin low for 100ms to perform a hard reset.
• RX & TX - OK now that I made you read all that you can actually use the UART pins. The module uses UART to send and receive commands and data. These pins are auto-baud so whatever baud rate you send "AT" after reset or boot is the baud rate is used. RX is into the module, TX is out of the module.
• RTSin - this is the hardware flow control pin. If you turn on flow control on the FONA you can use this pin to stop and start data transfer from the FONA 3G to your microcontroller
• CTSout - this is the hardware flow control pin. If you turn on flow control on the FONA you can use this pin to determine when the FONA 3G's serial buffer is full and you should stop and start data transfer to the FONA 3G from your microcontroller
• DTR - this is a hardware flow control pin, it can be used with the FONA 3G to hang up calls, control data/command mode for TCP/IP, ec.
• RI - this is the Ring Indicator. It is basically the 'interrupt' out pin from the module. It is by default high and can be configured to go low when a call is received. It can also be configured to go low when an SMS is received.
• SPK+ and - : This is for connecting an external 8 ohm speaker. The two pins are differential so they don't have output DC blocking capacitors. You cannot connect this to a stereo, powered speakers or other non-differential amplifier without adding a 100uF+ blocking cap in series to the + pin and then not using the - pin. Instead, your amp should use GND for the - reference
• MIC + and -: this is for connecting an external electret microphone, it will bias the mic with 2V. Most electrets will work just fine. No extra circuitry is required for the mic such as a biaser or amplifier, just wire it up directly!

LEDs

• PWR - Green! Lit when the module is booted and running
• NET - Red! You can use this for checking the current state without sending an AT command:
  Always on - the module is running but hasn't made connection to the cellular network yet
  800ms on, 800ms off - the module has made contact with the cellular network and can send/receive voice and SMS
  200ms on, 200ms off - the GPRS data connection you requested is active
  By watching the blinks you can get a visual feedback on whats going on.
• Charging - Orange! This is next to the microUSB jack. Indicates the onboard lipo charger is charging
• Done - Green! This is next to the JST jack. Indicates that the battery charging is done and the battery is full

Attaching Antenna & Battery

A battery, GPS antenna and GSM antenna is required! Use any Lipoly or LiIon 3.7V/4.2V battery

Check polarity for the battery!
Snap the uFL connector on, it will click when placed properly

SIM Card

You must insert a SIM card to do anything but the most basic tests. GPS does work without a SIM but of course you cannot send or receive texts, calls, etc!

If you'd like to use or test the FONA 3G you can do so right over the USB port, which is not just for charging, but is also a full interface to everything the module can do!

First up, you will still need a small Lithium Polymer battery to keep the power supply stable. You'll also likely want an antenna and SIM card. A microUSB cable is required. We've tested this on a Windows 7 computer, other operating systems may vary!

Insert the SIM card, connect the antenna(s) and plug in the micro USB cable from your computer to the FONA 3G

Then press the small KEY button next to the battery & cell antenna for 5 seconds. Then the computer will recognize a multi-type USB connection. Install the drivers

There are 4 devices created

•  A Modem device
• A USB diagnostics COM port
• A NMEA COM port (this is the raw GPS NMEA output)
• A USB AT port (this is how you can send commands to the module!)

You can connect to the AT com port at any baud rate and send AT commands like normal. This makes it super easy to test out commands

If you turn on the gps with the at+cgps=1 command in the AT serial port you can then connect to the NMEA COM port and see GPS NMEA data

We haven't tried out the Modem yet and the Diagostics USB port doesnt seem to respond (probably you need a special software package)

Wire up

After soldering headers to the FONA module, plug it into a breadboard. We'll use an UNO, other Arduinos may be different

• Vio connects to 5V (or, with a 3V logic Arduino, 3V)
• GND connects to GND
• Key connects to GND (always on)
• RX connects to digital 2
• TX connects to digital 3 (9 on Leo/Micro, 10 on Mega)
• RST connects to digital 4
  

Make sure a full LiPo battery is connected!

We'll be using software serial to talk to the module. The Mega ('2560 based) can't use Digital 3 for FONA TX, so use digital 10 instead.  The Leonardo and Micro ('32u4 based) can't use digital 3 for FONA TX, so use digital 9 instead.  See this page for other pins you can use for FONA TX (SoftwareSerial Receive) on the Mega, Leonardo, and Micro.

You can also try hardware serial, you'll need to update the sketch to indicate which Serial port you want to use

The FONA 3G adds 3G support but since it is a completely different chipset than the FONA 800/808 (Qualcomm not Mediatek) there are some significant differences between the two types of modules.

This is not an exhaustive list!

SMS

SMS's are indexed differently

FONA 800 & 808 start at 1 (one) where as the FONA 3G starts at 0 (zero)

SMS sending extra lines

After sending an SMS using AT+CMGS, the FONA 3G returns two sets of CRLF's that do not appear with the FONA 800 or 808.

SMS # query reply is different

If you request the # of SMS's on the SIM module with AT+CPMS? the FONA 800 & 808 reply starts with +CPMS: "SM_P" whereas the 3G starts with +CPMS: "ME"

Voice Calls

The hanging up command is ATH0 on the FONA 800 and 808 and ATH on the FONA 3G. You'll also have to send the FONA 3G a AT+CVHU=0 command to tell it to listen for the ATH command (it will say 'OK' but not actually hang up)

Misc

Battery voltage measurement with AT+CBC returns a 4-digit voltage in mV on the FONA 800 and 808. On the FONA 3G it's a floating point number in volts.

GPS

GSMLOC (location via triangulation of nearest cell towers) is supported by the FONA 800 and 808 but not 3G

Datasheets & Files

These are the datasheets for the cell module on the FONA 3G.

• SIM5320 AT Command set manual
• SIM5320 Hardware Design
• SIM5320 Specification
• GPRS / TCP/IP App note
• SIM5320 USB drivers (We tried this on windows sucessfully, also looks like there's some sort of linux drivers)
• EagleCAD PCB Files on GitHub
• Fritzing object in the Adafruit Fritzing Library

Product page at SIMCOM

Schematic

Click to enlarge

Fabrication Print

Dimensions in inches

GPS Rollover

In Nov 2019, the GPS unit in the FONA 'rolled over' - so dates will be off by 20 years. There is no firmware fix from SIMCOM for this issue. Please get year/month/day from the cell service instead of GPS

Large file transfer

You can use FTP with the FONA 3G, rozzie has some tips in the forums for how to use it for large file transfer!

AT&T vs T-Mobile 3G

The American band version of the FONA 3G covers dual-band UMTS/HSDPA 850/1900MHz WCDMA + HSDPA

In the USA, only AT&T has 850 MHz and 1900 MHz as the two supported HSPA bands. So if you use T-Mobile or a distributor of theirs, you will only get 2G support not full 3G! For 3G, stick to AT&T or check with the carrier that they have one of the dual-band UMTS/HSDPA 850/1900MHz WCDMA + HSDPA supported

Usage In Australia

Here's a note from Dan Clark

I've experienced similar issues with the FONA network. I've done a bit of research and here is my conclusions.

The Telstra frequency bands for 2G were 900/1800MHZ while the 3G bands for Telstra are 850MHZ/2100MHZ.
The European version product offers 900/2100MHZ bands while the American version offers 850/1900MHZ.

I've been using both the American and European models in regional Australia(poor reception), they were both operating fine until Telstra shut down the 2G network.
This resulted in the European version of the product being unable to work as it cannot connect to the Telstra 3G lower frequency band(the 3g band is 850 while the European model can only do 900). However upon trialing the American version, it operated fine as it does cover the required frequency for 3G connection. I have realized the American version would not be capable of providing connection to the high frequency 3G network(3G is 2100MHZ and American can only do 1900) but this is not an issue as the high frequency band is not available in rural Australia.

Also from my experience, the device can get RSSI signal but won't register unless the correct frequency bands are available. ie using a European version, I will get full RSSI strength but no network registration as the European version operates on 900MHZ, while Telstra 3G is 850MHZ.

One solution to this problem is to simply switch carriers(not a great idea if you are using this in regional areas like myself), or alternately use the American version of the device which is unfortunately not sold to Australia because .....?