The IsatPhonePro was released last summer surrounded by an excellent marketing campaign enuring that everybody knew about it. Initially it was not capable of sending and receiving data but Inmarsat promised that it would at some future point. After a few missed deadlines we were starting to become a little skeptical, however at the beginning of April and after a little firmware update we were able to use the data service.
We got straight on it and started testing our IsatPhonePro to see what it could handle. Inmarsat are claiming that the phone is capable of 2.4Kbps and it doesn't take much research on the internet to find people claiming all sorts of data rates with this phone. You have to be careful when comparing data rates as it can get very confusing and the people in the know tend to like to keep it this way as it means they can make some outrageous claims.
First lets start with the difference between bits and Bytes, they look very similar when abbreviated but are very different in size. A bit is notated as a little b and is either a single '0' or a single '1', while a Byte is notated as a capital B and is eight '0's or '1's strung together. Therefore a Bit is eight times smaller than a Byte. When claiming speeds manufactures tend to like to claim things in bits per second (bps) as it makes things sound faster.
So Inmarsat are claiming that the IsatPhonePro is capable of 2.4Kbps which I am sure it is but under a very certain set of circumstances that favor the phone and are unlike to experience in the real world. Now this is fine as its what all manufactures do hence why people write articles like this to try and demonstrate what devices are capable of in the real world.
If you see anyone claiming that they are capable of getting more than 2.4Kbps down either the Inmarsat or the Iridium then they are talking about compressed data and trying to mislead. For example if I had 36KBs (not Kbs) of data and was able to compress this by 50% down to 18KBs of data and then send it across the IsatPhonePro in 1 minute I could claim that I had an effective data rate of 4.8Kbps. This is because the data in uncompressed at the other end so as far as both ends are concerned 36KBs of data has been sent and it only took 1 minute. Taking compression into consideration when stating speeds is not very honest as you are really talking about how good your compression is not how fast the device is.
We tested the IsatPhonePro and the Iridium 9555 multiple times and with exactly the same 20KB file containing random data. The average time taken for the Iridium 9555 to send the request for the file and then receive it was 2 minutes 37 seconds. All together there was 28KB of received data including the request for the file and and the email that the file was contained within. So the Iridium achieved an average speed of 1.4Kbps in this test.
The IsatPhonePro took an average of 4 minutes and 42 seconds to request and download the file which again was a total of 28KB of received data. This means that the IsatPhonePro acheived an average speed of 0.793Kbps in this series of test.