Send and Receive SMS Text Messages Using a GSM GPRS Wireless Modem
If you need the ability to send SMS text messages from your website or Internet connected software, you will quickly discover several options such as using the free wireless carrier email to SMS gateways (ex. 5555551212@vtext.com), third party SMS gateways (ex. CellTrust HTTP API), direct connection to SMSC’s (after days of research and phone calls to AT&T, we couldn’t figure out how to do this), and GSM GPRS wireless modems.
The free SMS gateways are great if you know both the phone number and mobile carrier, and you don’t require delivery to or from a short code. If you don’t know the mobile carrier you can look it up through any number of free or paid third party API’s (CellTrust offers one). If you need to use a short code, then third party SMS gateways are your only choice. But at large volumes, the cost can really add up. GSM GPRS modems are the best choice if you need to send high volume, don’t know the carrier, and don’t need a short code. However, programming and scaling GPRS modems can be a challenge because you have to use AT commands that aren’t always implemented in a standard format and you also have to do deal with serial port communication (For a great tutorial, checkout: http://www.developershome.com/sms/). If only somebody made a GSM GPRS modem attached to a web server…. Somebody did, and I have to give it a very positive review.
We stumbled upon the SMSFinder while on a tech support call with Multi-Tech. We had purchased a GSM GPRS modem and we intended on programming it using AT commands to send and receive text messages. We found out from our very helpful tech support person (Multi-Tech support is excellent btw), that if we just wanted to send text messages, the SMSFinder is for us. The SMSFinder is a GPRS Wireless Modem, with an ethernet port, wrapped with a web server. Just slide in an active SIM card, plug it in, and your ready to go. It exposes a simple HTTP API for sending messages, along with a basic GUI web admin portal. The device handles queuing the requests if it gets behind. We have put multiple modems behind a load balancer, assigned it a VIP, and instantly have the ability to scale. The downside to this approach is that your messages will come from one or more phone numbers, not short codes. But if you need to inexpensively send a large volume of messages very cheaply (10,000 messages via a third party api will cost you about $500), and you don’t require a short code, then you should consider the SMSFinder.
Here’s a short summary of options for sending SMS test messages.
| Option | API | Cost | Deliverability | Carrier Required | Short Code Support | Receiving | Volume |
|---|---|---|---|---|---|---|---|
| Carrier Email to SMS Gateways | Free | Can be Slow | Yes | No | Yes, but requires inbound mail server. Needed to manage unsubscribes | Larger commercial volumes (> 1000/day) may cause you trouble with the wireless carriers | |
| 3rd Party Gateway API | HTTP, SOAP, Email | 1 to 6 cents per message | Fastest Delivery | No | Yes, either dedicated or shared | Yes via callbacks | Unlimited |
| GSM GPRS Modem | Hayes AT Commands | $200 to $700 + $50/month for unlimited sms wireless plan | 7 to 20 per minute | No | No | Yes | Unlimited Domestic |
| SMS Appliance (ex. Multi-Tech SMSFinder) | HTTP | $700 (1-port) + $50/month for unlimited sms wireless plan | 7 to 20 per minute | No | No | Yes via callbacks | Unlimited Domestic |
And one more thing, Multi-Tech is releasing a 4 and 8 port version in Summer of 2009.
Don’t Mix Brainstorming and Estimating Effort in the same Design Meeting
Recently, Derrek Long, my system architect, asked me to read a few pages from the book I.M. Wright’s Hard Code by Eric Brechner. He had observed issues our company was having with mixing brainstorming and scope cutting in the same meeting. Brechner describes over a few page in Chapter 5 how to avoid getting FOCKED, or “Failing to Orchestrate Collective Knowledge Effictively for Design”. Essentially, Brechnar preaches to have very specific goals for a meeting, and to avoid at all costs mixing goals, especially when the goals are completely opposite to each other.
After reading Brechner, and thinking about it for the last few weeks, I’ve expanded this idea out a bit further as to why mixing brainstorming and estimating effort during initial design meetings between the business stakeholders and development is a bad idea.
- Discussing effort for each idea discourages creativity when brainstorming. People will be less likely to offer “out of the box” or “half baked ideas” that need to be flushed out if they are afraid they will be scolded for coming up with something “too hard”.
- Dev often will give a big estimate when they don’t like an idea. So waiting to estimate the idea at a later time demonstrates that dev still put in the due dillagence to consider the idea and the estimate isn’t just based on dev not immediately liking it.
- Initial estimates given 10 seconds after hearing an idea in a brainstorming meeting will be less accurate. Dev needs time to absorb the idea, think it through, and then offer an estimate of effort. Even spending 5 or 10 minutes considering an idea results in the developer spending 100 times more time considering the idea and will result in a more accurate and reliable estimate.
- Other ideas presented later in the meeting might add further clarity to earlier ideas or might prevent the idea from needing estimation altogether.
I would love to hear from other people their experience with keeping brainstorming and estimating separate. If you have techniques you employ to do this, let us know!
About
Thanks for visiting! My name is Keith Forsythe and this is my blog about product development, product marketing, mobile devices and general business practices at an Internet Startup.
I am currently co-founder and Director of Product Development at RideCharge, Inc (Taxi Magic), a startup mobile and web taxi booking service. Prior to RideCharge, I was an IT project manager as CVS/Caremark, and a software engineer at Baxter Healthcare. I have a MS in E-Commerce Technolgy from DePaul University and a BS in Chemistry from the University of Illinois at Champaign Urbana.
