2006 November

 

 ProASM releases alternative Sentech MyWireless Dialler

November 19, 2006

 ProAsm has created a windows dialler application for the Sentech Modem, that replaces the default Sentech dialler, and displays signal strength with a higher frequency, and has some neat other features. http://www.unrealza.co.za/proasm/mywireless.html



 

 IPWireless P1C Modem Commands

The modem, when connected via USB, emulates a Hayes “AT” command set compatible modem. Some of the commands are extensions for 3G devices ratified the “3GPP TS 27.007 AT command set for 3G User Equipment (UE)”

at http://www.3gpp.org/ftp/Specs/html-info/27007.htm.

The IPWireless modem implements a very basic subset of this specification. Here is a list of known commands, and a description of what they do. This list isn’t exhaustive, there are some other commands, for PIN management etc, but I haven’t bothered to document those, as Sentech doesn’t requires SIM cards – hence the PIN functions don’t do anything. Also note that these are brief, generalized descriptions of what they do. For the full spec, read the 3GPP document.

!AT+CGMM – Get model ID

*Function:* Returns the model ID of the equipment.
*Example:*
AT+CGMM?
+CGMM: Phase 1(c)

0
OK

!AT+CGMR – Get firmware version

*Function:* Returns the firmware level of the modem.
*Example:*
AT+CGMR?
+CGMR: 4.2.1.1 / A1 (2.0) / A2 (2.0); 4.2.1.1

0

OK

!AT+CGSN – Get modem IMEI

*Function:* Returns the GSM IMEI unique identifier of the modem.
*Example:*
AT+CGSN?
+CGSN: 351152000146190

0

OK

!AT+CSQ – Get signal strength information

*Function:* Returns the signal strength percentage, RSCP, and ISCP
*Example:*
AT+CSQ
+CSQ: 29,99,-79,-95,5

OK
*Description:*
In this example, 29 is the reported percentage signal strength, 99=unknown fixed value,
-79 is the RSCP, and -95 is the ISCP. It is unclear what the final "5" indicates.

*Alternate example:* Query supported/range of CSQ values
AT+CSQ=?
+CSQ: (0-91,99),99,-116..-25,-116..-25

OK

!AT+COPS – Operator selection and querying.

*Function:* Returns/selects the Network provider
*Example:*
AT+COPS?
+COPS: 1,2,"00000"

OK

*Description:*
In the above example, the list of known operators was requested, returning Sentech's "00000", which
you will see in the dialler.
"2" is the numeric  ID for use in subsequent commands.
"1" is the current status of the provider. The following status codes apply:
"00000" is the alphanumeric operator ID.

:
0	unknown
1	available
2	current
3	forbidden

An operator Sentech is selected in the following fashion:
AT+COPS=~[,
,]

E.g.
AT+COPS=1,2,"00000"

Where "1" (mode) means manual selection, "2" means 'select-by-numeric-id', and "0000" is Sentech's
ID.

Other modes:
0	automatic ( field is ignored)
1	manual ( field shall be present)
2	deregister from network
3	beyond scope of this description...
4	manual/automatic ( field shall be present); if manual selection fails, automatic mode
        (=0) is entered

!AT+CBC – Get battery information

Function: Returns the signal strength percentage, RSCP, and ISCP
*Example:*
AT+CCBC
+CBC: 13,97

OK

*Description:*
In this example, 13 appears to indicate "AC Power". 97 is the battery level, in percentage.

Alternative example: Query supported/range of CBC values
AT+CBC=?
+CBC: (0,1,2,3,4),(1-100)

OK

It is interesting to note, that the modem appears to report values outside of the
range. (13 in the example).

!AT+CGATT – Get/set frequency information

*Function:* Get the frequency, and base station attached to
*Example:*
AT+CGATT?
+CGATT: 2506000, 7.68Mcps, 31, 126

OK
*Description:*
It's unclear what all these numbers mean, but at a guess 2506000 is obviously
the frequency used to talk to the currrently attached tower. 7.68Mcps is
probably the negotiated maximum speed, 31=unknown, and 126 is the base station
number.

*Function:* Clear frequency list
AT+CGATT=0
OK
AT+CGATT=1,0
OK

Description: Clears the modem's internal frequency list.
AT+CGATT? for instance, will report that the modem is not connected to any tower -
"+CGATT: -, -, -, -"

*Function:* Select a set of frequencies
AT+CGATT=1,,...

Freq, can be any of the three Sentech frequencies:

*Example:*
AT+CGATT=0
OK
AT+CGATT=1,0
OK
AT+CGATT=1,2518000,2506000,2530000

The modem will respond, immediately with "OK" if it was able to attach to a tower
using the specified frequency(ies). If not, it will not respond, until another character
is sent. This can be used to check of it's possible to attach to a tower at the specified
frequency, within a specific timeout.

If the modem attached, using the specified frequencie(s), AT+CGATT? will return the tower
details.

It would be nice if this command actually worked as one would expect it to. The modem however
seems to be very insistent on what tower it latches on, regardless of specified frequencies,
so the data in this command appears to be more of a "hint" to the modem than a set instruction.

The modem seems to scan a wide range of frequencies, regardless of this hint.


 

 MyWireless/IPWireless P1C USB Modem Drivers for Linux

I wrote a Linux device driver for the IPWireless USB modem that has been included since kernel 2.5 

These can now be found at http://www.neology.co.za/opensource/sentech-mywireless-ipwireless-p1c

I also have some old archives, and collections of tools, firwmare and an alternative driver which was written by some guys for Woosh in New Zealand over here.

The device driver was written by painstakingly reverse engineering the Windows driver using USBSnoopy.



 

 Linux Development – The pleasure and the pain

Developing software under Linux can be a pleasure. It can also be a real pain. The following are just *some* of my observations about it.

Why Linux, GNU, and GCC tools are great:

  • It’s the best standards-based compiler in the world:
    I mean it. Nothing beats it’s stability in terms of being able to gronk code written in ANSI, or ISO, or GNU’ish C.
  • Most cross platform toolchain:
    GCC, and tools are the most cross platform compiler, and from all compiler’s I’ve used, allows the most fine-grained control of code optimisation. Aside from that, the assembly code it produces is very optimal, regardless of the platform you code on. Hell, I can even cross-compile Windows code on Linux, and the resulting stuff runs better than what native compilers can produce.

Why Linux, GNU, and GCC tools suck

  • Newer versions of GCC suck:
    Specifically the 3.x series just plain suck. GCC 2.95.3+ are the most stable GNU compilers ever. I don’t know why they even bothered with the 3.x series. It just broke everything, and it’s speed/performance is atrocious. (update: GCC 4 again moved back to ‘stable’ predictable)
  • Lack of development IDE:
    I’m a vim, and grep man myself, but the fact is there are very few good IDE’s for the GCC collection. Sure, there are tools. I know, I’ve tried most of them. The fact is, that none of them come close to the INTEGRATED experience that is Microsoft’s Visual C++ (update: I refuse to Eclipse thank you)
  • Lack of integrated ASSEMBLY level debugger:
    Yes, I know about VGDB, and the myriad of other tools out there that front-end GDB, but let’s face it. They’re all still GDB, with a crappy shell. And GDB has never integrated well into any IDE. Hell, even free Windows debuggers (Assembly/source) such as OllyDbg kick the pants out of GDB.
    I know many would say that console level, command prompt driven debugging is the only way to go, but even Visual C++ is able to produce a _proper_ stack backtrace, and produce readable disassemblies from running code, even without debug information. OllyDbg’s code analysis takes it to the next level.Fact is, that even Visual C++’s debugging capabilities kicks GDB and any other available tool for Linux’s behind.
  • !MAN (manual pages) suck:
    Yes, I know that may sound weird. But manpages do suck. Sometimes the actual documentation is more damaging, than not having any documentation at all. Then, there’s the interface, and search capabilities, and just the arrangement of manual pages. Yes, I know there’s tools like apropos, and a myriad other to enhance the searching, but there’s still _nothing_ GNU tools can offer that matches the well maintained, and usable format of Microsoft’s MSDN library. It’s a pity.


 

 Legends – A spiritual successor to Tribes2

I’m one of the developers behind a game called Legends. Legends started out as a project to be what Tribes2, and Tribes1 never was, and then, it grew completely out of control. I’m officially the Linux port-monkey, and general “plumbing” coder for Legends.

Legends was made possible by the awesome people of Dynamix, who got shut down by Sierra. The lead developers then started a company called GarageGames, which licenses the Torque (ala Tribes2) game engine to developers for the meagre sum of $100.

That’s the best deal you can get for _any_ kind of game engine. Tribes1, and Tribes2 were well known for their excellent network code, and engine. Besides that, the engine has an open scripting interface, and runs on Linux, AppleMacintosh, and Win32.

To checkout, Legends go to http://www.legendsthegame.net/

Contributions are welcome. We need more sound specifically. The game is currently at no 9 on the HappyPenguin rankings, and is well known amongst the Gentoo crowd, and loved elsewhere.