Tuesday, January 26, 2010

ACPO Managers Guide

ACPO Managers Guide
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Good Practice and Advice Guide for Managers of e-Crime Investigations
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I telephoned and spoke with a personable Stephen Clarke today of the Police Central e-crime Unit (PCeU). PCeU is the department apparently responsible for the proper and appropriate dissemination of factual information to Managers (Clients and Stakeholders) for the Police. I contacted Stephen as I was disappointed with the inaccuracy promoted in the Guide that information about my organisation was wrong and was known to be wrong long before the Guide was published in July 2009.
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The information which I am referring to as inaccurate is on page 87 Appendix C details of Training Courses:
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Some examples of product based training are:
PhoneBase – Trew MTE offer a range of continuous professional development certificate and accredited courses.
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Industry and in the mobile telephone examination sections in the Police know that to be inaccurate for 2009 and comments I had back were they were surprised that statement was made as Phonebase training had ceased for a number of years.
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Stephen Clarke, who is the person mentioned as being responsible for the Guide being in the market place (being named as its 'Author'), actually isn't the Author in the true sense of the word. In fairness to Stephen his job is to compile the parts to formulate one package for delivery. He was unaware about the errors in the Guide apparently because others behind the scenes who have their hand in preparing the data assemble the 'researched' material compiled and send it to him.
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It becomes even more concerning when all the information promoted about the other people and companies is accurate; clearly any manager seeing my information will have noticed that the system attributed to me is not used anymore, there is no training for it now and hasn't been for some while. Was that deliberate by those who researched the material first before passing it to ACPO HQ?
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You see this type of inaccuracy published like this gives the impression that ACPO doesn't know what it is doing or talking about inspite of the fact Quality and Accuracy checking are two components lauded as fundamentally underpinning ACPO Guidelines. The impact of that is:
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- Firstly, ACPO Guidelines are quoted in our criminal courts of law informing the Judges and Jurors these are the standards the Police work too. That in itself is unfair to every officer or police staff who make reference to ACPO in their defence as why they followed certain procedures when the basis to the document is inaccurate;
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- Secondly, managers are likely to make public sector spending decisions based upon this public sector document; those managers were not given the public sector opportunity to know whether they were paying too much for training and the skillsets in the training to bring value to the money they were paying.
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- Thirdly, managers are still none the wiser as to the highly experienced training provided by TrewMTE and therefore the ACPO Managers Guide does not educate managers to the vital information they need to know in oder to take decisions.
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Tuesday, January 19, 2010

Location Area Codes (LAC)

Location Area Codes (LAC)

The desire to create databases containing MCC/MNC/LAC/CellID may seem a good idea but might produce inaccurate or erroenous results depending upon the way in which the information is used. It is known that LACs (and CellIDs for that matter) change and therefore a database becomes out of data fairly quickly.

LACs change for various reasons. Commonly LAC Dimensioning can be implemented due to heavy paging load or many LACs under one BSC causing frequent Location Updates are just two examples. The outcome of Dimensioning can require reprogramming BSC (GSM) / RNC(WCDMA) for each cell. Moreover, reprogramming at the MSC. On some occasions re-parenting at the MSC maybe required that requires re-programming LACs. Cell shapes, size and traffic capacity can change from the material time.

Unlike MCCs and MNCs, LACs are not published. LAC identifiers can by assigned by the network operator. It is essential as with all broadcast data to understand what the data mean and the data relevance to mobile telephone evidence.

Location Area Code (LAC) which is a fixed length code (of 2 octets) identifying a location area within a GSM PLMN. This part of the location area identification can be coded using a full hexadecimal representation except for the following reserved hexadecimal values:

0000, and FFFE

These reserved values are used in some special cases when no valid LAI exists in the MS.

The Location Area Identification is a type 3 information element with 6 octets length.
....8......7......6......5......4......3......2......1....
+-----------------------------------------------+
│ ...Location Area Identification IEI..│ octet 1
+-----------------------------------------------│
│ ....MCC digit 2 │ MCC digit 1..... │ octet 2
+-----------------------+-----------------------│
│ .....MNC digit 3 │ MCC digit 3.....│ octet 3
+-----------------------+-----------------------│
│ ...MNC digit 2 │ MNC digit 1...│ octet 4
+-----------------------------------------------│
│ .......................LAC......................│ octet 5
+-----------------------------------------------│
│ ............LAC (continued)............│ octet 6
+-----------------------------------------------+
Figure 10.5.3: Location Area Identification information element


Table 10.5.3: Location Area Identification information element
+----------------------------------------------------------------------+
MCC, Mobile country code (octet 2 and 3)
The MCC field is coded as in CCITT Rec. E212, Annex A.

If the LAI is deleted the MCC and MNC shall take the
value from the deleted LAI.

In abnormal cases, the MCC stored in the mobile
station can contain elements not in the set
{0, 1 ... 9}. In such cases the mobile station should
transmit the stored values using full hexadecimal
encoding. When receiving such an MCC, the network
shall treat the LAI as deleted.

MNC, Mobile network code (octet 3 bits 5 to 8, octet 4)
The coding of this field is the responsibility of each
administration but BCD coding shall be used. The MNC
shall consist of 2 or 3 digits. For PCS 1900 for NA, Federal
regulation mandates that a 3-digit MNC shall be used.
However a network operator may decide to use only two
digits in the MNC in the LAI over the radio interface. In this
case, bits 5 to 8 of octet 3 shall be coded as "1111".
Mobile equipment shall accept LAI coded in such a way.

Note 1: In earlier versions of this protocol, the possibility to use a one digit MNC in LAI was provided on the radio interface. However as this was not used this possibility has been deleted.

Note 2: In earlier versions of this protocol, bits 5 to 8 of octet 3 were coded as "1111". Mobile equipment compliant with these earlier versions of the protocol may be unable to understand the 3-digit MNC format of the LAI, and therefore unable to register on a network broadcasting the LAI in this format.

In abnormal cases, the MNC stored in the mobile
station can have
- digit 1 or 2 not in the set {0, 1 ... 9}, or
- digit 3 not in the set {0, 1 ...9, F} hex.
In such cases the mobile station
shall transmit the stored values using full hexadecimal
encoding. When receiving such an MNC, the
network shall treat the LAI as deleted.

The same handling shall apply for the network, if a
3-digit MNC is sent by the mobile station to a network using
only a 2-digit MNC.

LAC, Location area code (octet 5 and 6)
In the LAC field bit 8 of octet 5 is the most
significant bit and bit 1 of octet 6 the least
significant bit.


The coding of the location area code is the
responsibility of each administration except that
two values are used to mark the LAC, and hence the
LAI, as deleted. Coding using full hexadecimal
representation may be used. The location area code
consists of 2 octets.


If a LAI has to be deleted then all bits of the
location area code shall be set to one with the
exception of the least significant bit which shall be
set to zero. If a SIM is inserted in a Mobile Equipment
with the location area code containing all zeros, then
the Mobile Equipment shall recognise this LAC as part
of a deleted LAI
+-----------------------------------------------------+

More on Cell Site Analysis: http://cellsiteanalysis.blogspot.com

Location Area Codes (LAC)

Location Area Codes (LAC)

The desire to create databases containing MCC/MNC/LAC/CellID may seem a good idea but might produce inaccurate or erroenous results depending upon the way in which the information is used. It is known that LACs (and CellIDs for that matter) change and therefore a database becomes out of data fairly quickly.

LACs change for various reasons. Commonly LAC Dimensioning can be implemented due to heavy paging load or many LACs under one BSC causing frequent Location Updates are just two examples. The outcome of Dimensioning can require reprogramming BSC (GSM) / RNC(WCDMA) for each cell. Moreover, reprogramming at the MSC. On some occasions re-parenting at the MSC maybe required that requires re-programming LACs. Cell shapes, size and traffic capacity can change from the material time.

Unlike MCCs and MNCs, LACs are not published. LAC identifiers can by assigned by the network operator. It is essential as with all broadcast data to understand what the data mean and the data relevance to mobile telephone evidence.

Location Area Code (LAC) which is a fixed length code (of 2 octets) identifying a location area within a GSM PLMN. This part of the location area identification can be coded using a full hexadecimal representation except for the following reserved hexadecimal values:

0000, and FFFE

These reserved values are used in some special cases when no valid LAI exists in the MS.

The Location Area Identification is a type 3 information element with 6 octets length.
....8......7......6......5......4......3......2......1....
+-----------------------------------------------+
│ ...Location Area Identification IEI..│ octet 1
+-----------------------------------------------│
│ ....MCC digit 2 │ MCC digit 1..... │ octet 2
+-----------------------+-----------------------│
│ .....MNC digit 3 │ MCC digit 3.....│ octet 3
+-----------------------+-----------------------│
│ ...MNC digit 2 │ MNC digit 1...│ octet 4
+-----------------------------------------------│
│ .......................LAC......................│ octet 5
+-----------------------------------------------│
│ ............LAC (continued)............│ octet 6
+-----------------------------------------------+
Figure 10.5.3: Location Area Identification information element


Table 10.5.3: Location Area Identification information element
+----------------------------------------------------------------------+
MCC, Mobile country code (octet 2 and 3)
The MCC field is coded as in CCITT Rec. E212, Annex A.

If the LAI is deleted the MCC and MNC shall take the
value from the deleted LAI.

In abnormal cases, the MCC stored in the mobile
station can contain elements not in the set
{0, 1 ... 9}. In such cases the mobile station should
transmit the stored values using full hexadecimal
encoding. When receiving such an MCC, the network
shall treat the LAI as deleted.

MNC, Mobile network code (octet 3 bits 5 to 8, octet 4)
The coding of this field is the responsibility of each
administration but BCD coding shall be used. The MNC
shall consist of 2 or 3 digits. For PCS 1900 for NA, Federal
regulation mandates that a 3-digit MNC shall be used.
However a network operator may decide to use only two
digits in the MNC in the LAI over the radio interface. In this
case, bits 5 to 8 of octet 3 shall be coded as "1111".
Mobile equipment shall accept LAI coded in such a way.

Note 1: In earlier versions of this protocol, the possibility to use a one digit MNC in LAI was provided on the radio interface. However as this was not used this possibility has been deleted.

Note 2: In earlier versions of this protocol, bits 5 to 8 of octet 3 were coded as "1111". Mobile equipment compliant with these earlier versions of the protocol may be unable to understand the 3-digit MNC format of the LAI, and therefore unable to register on a network broadcasting the LAI in this format.

In abnormal cases, the MNC stored in the mobile
station can have
- digit 1 or 2 not in the set {0, 1 ... 9}, or
- digit 3 not in the set {0, 1 ...9, F} hex.
In such cases the mobile station
shall transmit the stored values using full hexadecimal
encoding. When receiving such an MNC, the
network shall treat the LAI as deleted.

The same handling shall apply for the network, if a
3-digit MNC is sent by the mobile station to a network using
only a 2-digit MNC.

LAC, Location area code (octet 5 and 6)
In the LAC field bit 8 of octet 5 is the most
significant bit and bit 1 of octet 6 the least
significant bit.


The coding of the location area code is the
responsibility of each administration except that
two values are used to mark the LAC, and hence the
LAI, as deleted. Coding using full hexadecimal
representation may be used. The location area code
consists of 2 octets.


If a LAI has to be deleted then all bits of the
location area code shall be set to one with the
exception of the least significant bit which shall be
set to zero. If a SIM is inserted in a Mobile Equipment
with the location area code containing all zeros, then
the Mobile Equipment shall recognise this LAC as part
of a deleted LAI
+-----------------------------------------------------+

More on Cell Site Analysis: http://cellsiteanalysis.blogspot.com

Sunday, January 03, 2010

Victorian Texting

Victorian Texting

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During the Christmas 2009 break I managed to visit and take the tour of Porthcurno Telegraph Museum in Cornwall (
http://www.porthcurno.org.uk/). A truly amazing place, full of historical artefacts depicting the history of telegraph, morse code etc. I recommend all UK and international examiners and experts who haven't been to the Museum to visit and learn about the history of telegraphy communications, its role enabling communications around the British Empire when it covered two-thirds of the world, its links to wireless communications and developed telegraphy devices and services associated with modern mobile communications today.

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"Victorian Texting" is a good example of one such development associated with telegraph and mobile communications. I have not been able to trace the precise origin how the label 'Victorian Texting' came about but perhaps it originated in the latter part of the 20th century following the introduction of mobile phones and short message service (SMS) text messages.

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Victorian Texting was made possible with the use of the Wheatstone's ABC Telegraph originated in 1842 developed by the English physicist and inventor Sir Charles Wheatstone (1802-1875).
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Image 1: Charles Wheatstone - Illustration by Mary Bellis
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The significant difference between morse code and morse code devices (already in use at that time) and Wheatstone's ABC Telegraph is that it was noted that with the latter device that it was an example of "de-skilling". Unlike Morse telegraphs, no knowledge of a code was needed. The button next to the desired letter was held down and the handle cranked. The needles of the instruments at both ends moved until they pointed to the chosen letter. The foreground part of the instrument is the transmitter, and the part at the back is the receiver (commentary from BT Museum Memorial Pages - Telegraphy 1).

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Image 2: Wheatstone's ABC Telegraph
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In action the operator of the ABC Telegraph could only communicate for a short distance due to the electricity needed to transmitter to the distant receiver. a cartoon depicting the use of the ABC Telegraph can be seen below (created by the engineer and cartoonist Tim Hunkin - www.timhunking.com)

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Image 3: Hunkin's cartoon depicting the use of Wheatstone's ABC Telegraph


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The Porthcurno Telegraph Museum website has a useful webpage that allows visitors to their website to simulate sending a text message on the Wheatstone's ABC Telegraph, so do give it a try (http://www.porthcurno.org.uk/html/object4.html).
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Image 4: Porthcurno Telegraph Museum interactive webpage - Wheatstone's ABC Telegraph
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Telegraph - Morse Code
The above is, of course, not the first time developments associated telegraph has been linked with mobile communications texting. For instance, the "Special" tone available to users of Nokia phones when receiving SMS (text messages) is actually Morse code for "SMS". Similarly, the "Ascending" SMS tone is Morse code for "Connecting People," Nokia's slogan. The "Standard" SMS tone is Morse code for "M" (Message).
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Reference Sources: