What's a "long message"?

A standard SMS, whether you're sending from your mobile or a web based SMS provider, is 160 characters long based on the GSM alphabet.

Before I go further, I'd like to quickly cover off what the GSM alphabet is to make it a bit clearer - it's an alphabet where the characters equal 7 bit (for standard messages) and includes letters, numbers, spaces, carriage returns, commas, etc... Not every symbol in the world falls into the GSM alphabet, and generally when that happens the networks interpret that character as something else, but that's another blog for another day.

So back to the original question of what is a long message? Well, it's where messages are stacked up like a club sandwich and sent out as a single message.

The way it's done is by taking 7 characters from the preceding SMS to form the header for the proceeding message so that when the handset receives the messages it can put them together in the correct order so it appears to be one long message.

So for example if you sent a message which had 200 characters in it, then the first message would be 153 characters long, with 7 characters forming the header for the next message, and the second message would be 47 characters long.

In a lot of cases long messaging isn't really required, for example for appointment reminders you generally wouldn't use more than 160 characters, and in a lot of cases, you probably wouldn't even get close to that limit either, however if you were using it to send support tickets out, then in that case you might use quite long long messages, so it's really dependent on the application.