If you like obscure facts, then this may be just up your street. Importantly, text messaging is one the of those services originally developed for GSM that has remained largely unchanged. Nokia have set out ten facts at the link below that they have gathered together about text messaging. For instance, as Nokia records:
TEN. Texting is the leading cause of tenosynovitis, which is an inflammation in the thumb caused by constant text-messaging. (It’s like tennis elbow but smaller and less sporty.)
See more details at the link below:
Previously at my blog, I unearthed and presented details of a development by Sir Charles Wheatstone (1802-1875) of texting in the Victorian era called the Wheatstone ABC Telegraph, which can be found here:
Some other useful facts helpful to investigation for mobile telephone evidence.
DID YOU KNOW?
For mobile circuit switched SMS messaging as an investigator reviewing the various typical transfer Cases (A-F) to see which applies to the evidence is important. Considering transfer conditions are also undertaken for GPRS and WCDMA.
Case A: Mobile originating short message transfer, no parallel call.
Case B: Mobile terminating short message transfer, no parallel call.
Case C: Mobile originating short message transfer, parallel call.
Case D: Mobile terminating short message transfer, parallel call.
Case E: Mobile terminating short message transfer together with Inter‑MSC hand over, parallel call.
Case F: Mobile terminating short message transfer on SDCCH channel together with Inter‑MSC hand over.
However transfer cases are only one aspect, and when dealing with text messages understanding relevant instructions regarding the storage desitnation for a text messages are defined by Classes (0-3) :
0 0 Class 0
0 1 Class 1 Default meaning: ME-specific.
1 0 Class 2 (U)SIM specific message
1 1 Class 3 Default meaning: TE specific.
SMS text message investigation doesn't end there as there are other aspects to consider such as the coding schemes used for the text messages, which can influence the maximum length of text messages, thus the user data length of a message. Commonly, the following coding schemes referred to are:
7-bit data - default GSM 160 characters (maximum 140 Octets)
8-bit data - user defined data (maximum 140 Octets)
16-bit data - user data up to 70 UCS2 characters (maximum 140 Octets)
But data coding scheme investigation doesn't stop because there are other aspects to messaging such as Cell Broadcast where 7-bit data coding allows for up to 93 characters, 8-bits data user defined is upto 82 Octets, but only 41 characters where UCS2 is used, are relevant. USSD messages using 7-bit data coding can be up to 182 characters. In some instances, handsets sending MMS messages may only allow up to 120 characters to be attached with an image/photo.
There are of course a number of other technical aspects to consider, and not everything has been discussed above. Where training investigators or dealing with evidence, I always make the caveat that it may be easy to accept text messages on face value once the text message message has been recovered from logical storage or free space (deleted), however analysis of the TP-UD header is extremely important task to perform.
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