Texas Instruments has released many overhead graphing calculators. These models are connectable to an external panel called 'ViewScreen' which just had to be put on a overhead projector.
However, what's wrong with this approach is the need for a special calculator provided with the appropriate ViewScreen connector, and the need for long cables which can cause accidents.


The company "Stokes Publishing Company" has a different approach. In partnership with leading calculator manufacturers (Texas Instruments, Casio and Sharp), it produces under the name "The Educator overhead calculator" a range of transparent basic and scientific calculators, which can therefore directly be put on a projector !

Transparent basic calculators which don't need much power do not even exceed the thickness of a credit card and can be directly powered by the lighting provided by the overhead projector.

Today for you on TI-Planet, after the first talking graphing calculator or the first color graphing calculator, let's have a look at the first transparent graphic calculator !
Sold as new for around $300, it's much more reasonable than the 600$ priced TI-84 Plus Orion talking graphing calculator.


Indeed, Stokes Publishing Compagny created in partnership with Texas Instruments calculator the first (and only) transparent graphic calculator, based on TI-73 Explorer, an entry-level graphing calculator marketed among others in North America, India , Asia , the Middle East, Australia and New Zealand. The TI-73 Explorer is the first TI non-CAS calculator using the Flash technology, released in 1998, one year before the TI-83 Plus. We will be refering to the latter when it comes to making comparisons.

Opening the box reveals us :

• a great bicolor case stamped with "Calculator Keeper"
  
• the official TI teacher activities book: "TI-73 - A Guide for Teachers ", prepunched
  
• a brochure showing the different Stokes Publishing Company products

Let's now open the case. It reveals us :

• the official handbook of the 'normal' TI-73 Explorer in a dedicated slot secured by two scratch bands
• specific instructions for battery replacement for the transparent TI-73 Explorer
• instructions to contact TI for support, although this is not the manufacturer
• a product registration card
• the TI-Product 1.1 CD specific to the TI-73 Explorer

This content removed, we can finally see the transparent TI-73 Explorer, surrounded by various accessories :

• 4 AA (not AAA unlike the 'normal' TI-73 Explorer batteries)
  
• a fastening cord
• the TI-Graph Link USB (aka SilverLink) cable for data transfer with a computer ;D
  (at this price, it's perfectly normal for this cable to be provided - a big problem with the twice more expensive TI-84 Plus Orion)
  
• a long 70cm transfer cable to connect to another calculator, doubly secured by two fuses at each end ;D

Finally, we're reaching this great calculator. It takes the form of a double frame hollowing therein two transparent rectangular areas :

• one for the keyboard
• one for the screen

So those two areas are what is going to be shown by the projector.


On the back, like the 'normal' TI-73 Explorer we note the presence of a compartment for the backup battery.
However, a mysterious the reset button missing from the original model is surprising us .

On the right we're finding the 2.5mm mini-jack communication port for connection to another calculator or a computer.
There is also a specific adjustment knob which controlling the opacity of the screen base color.


On the top, the cord can be used with some holes in the corners.


Finally let's insert the batteries and let's go!


Let's try to find out if it's using a normal TI-73 Explorer OS, or if it requires a specific OS like the TI-84 Plus Orion talking graphing calculator.
Apparently, calculator is coming with the penultimate official OS, version 1.90.
It has almost 25K of RAM free, suggesting a chip of 32KB, usual on TI-z80 graphing calculators technology.
However, we can be surprised at first by the archive (or storage) memory, where it says 8 free spaces. In fact, it means 8 free memory pages, the memory page beeing 16KB on TI-z80 calculators technology. So this makes us 8x16=128KB , against 160KB for the TI-83 Plus which therefore offers 10 free memory pages for archive.


A priori, the OS is therefore perfectly normal. Let's try to see if we can flash another version of the OS...
Unlike the TI-83 Plus, the link menu is not directly accessible from the keyboard . Indeed it takes the form of a permanent 'fake' unremovable Link application listed in the applications menu, like the Finance application on the TI-83 Plus. However, unlike the TI-83 Plus, it does not offer the ability to transfer an OS between two calculators.
So let's send the latest 1.91 OS from a computer, which works perfectly,  further confirming the identical behavior to a 'normal' TI-73 Explorer !


Note that the calculator is now offering us 12 free memory pages for archive instead of 8, for a capacity of 12x16=192KB higher than 160KB capacity of the TI-83 Plus !
Indeed, on the TI-73 Explorer, the reserved archive memory space is variable and depends upon the installed OS version :

Calculator	OS	Archive memory pages	Archive memory capacity	Total Flash chip capacity
TI-73 Explorer	1.3004 - 1.40	4	64 KB	512 KB
TI-73 Explorer	1.50 - 1.90	8	128 KB	512 KB
TI-73 Explorer	1.91	12	192 KB	512 KB
TI-83 Plus TI-83 Plus.fr (blue)		10	160 KB	512 KB
TI-84 Plus Pocket.fr TI-84		30	480 KB	1024 KB
TI-83 Plus.fr USB (black) TI-83 Plus Silver Edition TI-84 Plus Silver Edition TI-84 Plus Pocket SE		96	1536 KB	2048 KB
TI-84 Plus C Silver Edition		224	3584 KB	4096 KB

By accessing the self-test menu as on a 'normal' TI-73 Explorer, we also get the boot code version, 1.3007, the last one, once again perfectly normal.


You can also send older OS like 1.85, but you cannot go below. Indeed, the last 1.3007 Boot Code contains an anti - downgrade which rejects any OS with a lower version number.
(but remember we have the TI-73 Explorer RSA private keys if you absolutely want to have a smaller archive area...)



In the end, an excellent product for the quick and easy overhead of graphing calculators without all the technical disadvantages of a computer projector.
Despite obvious hardware changes, operation, functionality and compatibiliy stayed the same as on the 'normal' TI-73 Explorer, a great performance!


Source : http://tiplanet.org/forum/viewtopic.php?f=41&t=13517&lang=en

Link : *overstock* - Get the last TI-73 overhead units in the complete above pack directly from the manufacturer for only 25$

Until now, your TI-Nspire could not read documents files other than those created by the TI-Nspire software.
It was not possible to put on your calculator DOC/DOCX (Microsft Word), ODT (OpenOffice Write) or PDF files (Adobe Acrobat).
You couldn't either convert those documents to the TI-Nspire document format as it does manage very limited formatting options.
A solution was the conversion of these documents into BMP, JPEG or PNG images.
Unfortunately, the TI-Nspire system provides a very limited image reader without any zoom or scrolling support, thus limiting the images to a maximum size of 318x212 pixels inadapted to US letter documents.

A solution came with the mViewer image reader for owners of TI-Nspire still able to install Ndless.


A drawback of this solution however, was to have a different image for each page, and therefore constantly have to close and reopen images for a document with several pages.

Alas, Texas Instruments decided for back to school 2013 to permanently block any possibility of installing Ndless on new TI-Nspire CX hardware revision 'J', thus creating an unfair inequality among buyers in regards to their future exams where some of them will still be able to build a real world of documents on their TI-Nspire while the others nothing, causing discontent among those last purchasers who can consider having been deceived after being forbidden features granted to their predecessors and which were often one of their purchase criteria.



Today, we're not going to reduce this inequality, quite the contrary...  in the next few lines, some of you may explode with joy while the others may be completely disgusted...



Because tonight is a great day in the history of the TI- Nspire ...
Legimet was able to port the MuPDF library  and has just released the first third-party document reader for TI-Nspire CX and TI- Nspire CM !
Named nPDF, it supports PDF, XPS and CBZ documents.

Note that so far it does not work on classic TI-Nspire. But anyway, the program is already 8MB large and wouldn't let you with many space left for those documents on such calculators.

Compered to the previous mViewer solution, advantages of this new player should be:

• no need to bother looking for a tool to convert your documents to images any more, or even worse to do it manually
  
• no need to waste time opening multiple files on the calculator any more before finding the right page of the document

I was initially quite skeptical on the PDF support, as it is not a free format and did undergo many changes in years. However, I've tested several complex documents with many images and tables in addition to the text and have been amazed by an absolutely perfect display !

For example, here below, reading the 7^th of the 125 pages of the Getting started Started with the TI-Nspire ™ CX / TI-Nspire CX CAS Handheld .




Even if the nPDF reader is an extraordinary technical performance, it suffers (at least for now) from many drawbacks and limitations:

• no possibility to zoom
• no horizontal scrolling (all the pages are automatically scaled to the width of the screen, 320 pixels)
  
• no button to skip to the previous/next page (you've got to scroll to the bottom/top of a page in order to move to the next/previous) :(
  
• no continuous scrolling (pressing up/down arrows just produces a simple little up/down scroll, you then have to release the key and repress it, and again and again...) :(

Small things, whose many would be certainly easy and quick to fix with very gew C code lines, it's the matter of a simple weekend, but which for now are going to litterally ruin your user experience, unless you're happy with the video below... :(


Note that nPDF did crash here on the last page change. I think I could spot the problem. We notice indeed that when we're reaching the bottom of a page, the reader can sometimes cross the bottom page which displays some noise lines on the bottom of the screen. This happens with documents whose page height is not a multiple  of the vertical scrolling step. At this point, the reader reads random data outside of the memory allocated for ??the page data, which actually causes such crashes easily.


Briefly, in its current version 0.1, nPDF will be the right thing :

• to documents with very few pages (because of the crash risk on page changes)
  
• to multi-page documents requiring no or very little vertical scrolling (US letter landscape format for example - because of the non-continuous vertical scrolling)
  
• to one paged documents for those requiring vertical scrolling (because of the absence of keys to move to the next/previous page)
  
• and to documents with text large enough to be readable even once resized to 320 pixels wide (because of the automatic resizing to 320 pixels wide without any zoom possibility)

In my opinion, nPDF is not yet an end-user acceptable alternative to mViewer for reading documents on the TI-Nspire , but it's perfectly able to surpass it and to become the main TI-Nspire document reader before your 2014 exams, unfortunately only for some of you , I know, if the author has time to continue its development for the end-user now! ;D

So do not hesitate to thank the author, support him or encourage him, and even making your own comments or suggestions. ;)



Source and download: http://ourl.ca/20218

Cross-posted from: http://tiplanet.org/forum/viewtopic.php?t=13557&p=153843&lang=en

Just like the TI-Nspire OS 3.6 had been found on the Texas Instruments website seven weeks ago, the TI-Nspire softwares 3.6 have just been discovered and this suggests that we are getting closer and closer to the official release of version 3.6 !

Their version number is 3.6.0.546 , exactly the same as the OS version. So it seems that the found OS was really the one intended for the release and we do not know the reason for this period of 7 weeks.



If you have already specified license number to use the TI-Nspire software on your computer, it will automatically be recovered during the update. If you were in the evaluation period, it is not reset and will go on unaltered.

]Note that you can combine several evaluation periods without a license on one computer for up to 300 days (10 months), by sucessively installing and using different editions of the TI-Nspire software. But this means you musn't not install/launch the new edition before the former edition evaluation period has expired:

• TI-Nspire CAS Teacher Software (90 days)
• TI-Nspire CAS Student Software (30 days)
• TI- Nspire CAS Teacher Software Navigator (30 days)
• TI-Nspire Teacher Software (90 days)
• TI-Nspire Student Software (30 days)
• TI-Nspire Navigator Teacher Software (30 days)

Beware, it has not been well explored so far, but if you update your software to version 3.6, it is possible that some documents you are going to create with it in the future will no longer be usable with the the old 3.1 and 3.2 OSes.



In a previous news, we noticed that TI-Nspire units running OS 3.6 were unable to connect to a TI-Navigator wireless network managed by the TI-Nspire Navigator 3.2 software.
We assumed that it was either a bug in the OS, or that there had been some changes in the witeless protocol with version 3.6.

The changes have now been officially confirmed by TI. If you use a TI-Navigator wireless network, they advise you to update the calculators with OS 3.6 before updating the TI-Nspire Navigator software to version 3.6.

If you don't comply with this, wireless connectivity will be permanently lost and calculators will all have to be connected one after the other in USB in order to be updated to 3.6 and to get back the wireless connectivity. The TI-Nspire Navigator 3.6 is also prompting you for this on its first launch:

The TI-Nspire Navigator 3.6 software also comes with a new firmware 3.6.0.19 for the TI-Nspire Navigator access Point and makes you install it on its first launch. Fortunately, in practice this does not appear to affect the ability of the access point to communicate with TI-Nspire handhelds running OSes 3.1 and 3.2 with the TI-Nspire Navigator 3.2 software.


Let's sum up the problem :

• TI-Nspire calculators running OSes 3.1 or 3.2 can not communicate properly with the TI-Nspire Navigator 3.6 software
• TI-Nspire calculators running OS 3.6 can not communicate properly with the TI-Nspire Navigator 3.2 software

In both cases, the wireless network status on the handheld gets stuck in the following state:


For schools using a set of calculators belonging to them, it's just a simple matter of choice.

For the teacher who accepts on his TI-Nspire Navigator wireless network the personal calculators of his students, this change is extremely problematic. In fact:

• if he's using the TI-Nspire Navigator 3.2 software, he will have to forbit his students to install OS 3.6 on their own calculators
• if he's using the TI-Nspire Navigator 3.6 software, he will have to force his students to install OS 3.6 on their own calculators...

In the absence of apparent new features or a noticeable hacking interest for such networks, we may wonder about the reasons for a sudden change in the wireless network protocol, and if it is not rather a pretext to force massive updates to OS 3.6.



Source: http://tiplanet.org/forum/viewtopic.php?t=13525&p=153481&lang=en

Downloads:

• TI-Nspire Software Teacher Edition 3.6 (for Windows - 90 days)
  
• TI-Nspire Software Student Edition 3.6 (for Windows - 30 days)
  
• TI-Nspire Software Navigator Edition 3.6 (for Windows - 30 days)
  
• TI-Nspire Software Teacher Edition 3.6 (for Mac - 90 days)
  
• TI-Nspire Software Student Edition 3.6 (for Mac - 30 days)
  
• TI-Nspire Software Navigator Edition 3.6 (for Mac - 30 days)

(each edition of TI- Nspire software contains two versions of the software, CAS and non-CAS, each with separate and independent evaluation periods which will start on the first launch of its version)

Like every year, Ticalc.org is organizing the POTY (Program of The Year), an event in which the best TI calculators programs of the year are going to be elected into three categories:

• TI-z80 (TI-83 Plus, TI-84)
  
• TI-68k (TI-89, TI-92 Plus, TI-Voyage 200)
  
• TI-Nspire

A necessary condition for the choosen programs is to be uploaded on the Ticalc.org website.

So we invite you to publish your programs on Ticalc.org, especially if they are TI-Nspire or TI-68k programs.
Indeed, competition is relatively low in those categories, with very few programs have been published on Ticalc.org this year.


Source : http://www.ticalc.org/archives/news/articles/14/148/148438.html
Cross-posted from : http://tiplanet.org/forum/viewtopic.php?t=13474&p=153040&lang=en

Many of you chose the TI-Nspire CX for back to school 2013, hoping to be able to play Game Boy Advance games or to store scrollable and zoomable images with mViewer,  and therefore many of you have been disappointed not to be able to use the required tools anymore.
Indeed, Texas Intruments banned community jailbreaks Ndless and nLaunch on their new TI-Nspire CX hardware revision J and later.

But apparently, this was not enough for TI. With the release of the OS 3.6, TI tried has tried to ban Ndless and nLaunch from older TI-Nspire models and hardware revisions too.

In fact, once installed OS 3.6 :

• forbids you to downgrade to any older OS version including the 3.1 version required by Ndless
• installs the new Boot2 3.2.4 which is incompatible with nLaunch
• self-destructs itself after its first start if any resource is modified or absent from the installation file (like Boot2 3.2.4 or samples removed with TNOC), but still increases the minimum installable OS version to 3.6, making the calculator unusable until you accept to install the full OS 3.6 with its Boot2 3.2.4...

The first workaround was out within 24 hours after the discovery of OS 3.6, as a patched OS for the TI-Nspire CX CAS to be used with nLaunch, followed a week later by a similar patch for the TI-Nspire CX.

So, for the first time in the history of the TI community, this was a widely illegal infringement because of the distribution of modified executable copyrighted code from TI.
Fortunately, Excale and Lionel Debroux analyzed the modified versions of OS 3.6 and ported all necessary chances in a new version of nLaunch! nLaunch now dynamically patches the OS 3.6 when detected and there is no use of the counterfeit anymore!



Today we finally released a version of our Ndless/3.6 switching pack using the new nLaunch and all links to counterfeits have been removed from the site.

This pack will enable TI-Nspire still able to use the OS 3.1:

• to use the new OS 3.6 without having to give up Ndless / Nlaunch
  
• to be able to return to the OS 3.1 with Ndless anytime without the need of any computer!

There is now support for TI-Nspire monochrome models . All supported models are:

• TI-Nspire + TI-Nspire TouchPad
• TI-Nspire CAS + TI-Nspire CAS TouchPad
• TI-Nspire CX + TI-Nspire CX-C
• TI-Nspire CX CAS + TI-Nspire CX-C CAS

Compared to the old Ndless/3.2 switching pack, the new installation tutorial for the TI-Nspire CX has been greatly improved and simplified ! ;D
For monochrome TI-Nspire you had reported us several errors with the ntnoc tool used in the pack. These errors were coming from the low capacity on these models (only 32MB NAND), in which no less than three TI-Nspire OS have to fit during installation. The new installation tutorial for the TI-Nspire monochromes takes this into account and has the same manipulations in a different order which does not seem to trigger any error anymore! ;D
The installation has been tested several times for hours and days without any problem on no less than 7 different TI-Nspire models including 5 monochrome ones.



It looks like a great achievement, doesn't it? But it's not a victory for the community. Indeed, this package just help current Ndlessable handhelds to go on using Ndless and doesn't make Ndless installable on more handhelds at at all...
Ndlessable TI-Nspire handhelds therefore continue to decrease, just not as fast or as far as TI had planned.

We have no illusions: when the popup about the availability of the new OS 3.6 will be trigerred soon in TI-Nspire softwares, most users will of course update without seeking any information online.
TI has therefore not completely eradicated Ndless on older models and hardware revisions, but it remains huge victory: TI almost eradicated Ndless on older models and hardware revisions.



Download :
Ndless/3.6 switching pack

Link :
Installation Tutorial for Ndless/3.6 switching pack

Source :
http://tiplanet.org/forum/viewtopic.php?t=13311&p=151413&lang=en

My deepest sympathy to the Omnimaga team.


There are two types of TI-Nspire calculators:

• CAS models which return expressions you can transform: TI-Nspire CAS+, TI-Nspire CAS , TI-Nspire CX CAS , TI-Nspire CM CAS...
• non-CAS models which simply return numbers like any normal calculator: TI-Nspire+, TI-Nspire , TI-Nspire CX, TI-Nspire CM...

Some exams in some countries (United States, Portugal...) forbid the use of CAS calculators. That's why TI has split the TI-Nspire handhels in two sister lines. It is obvious that you can't (at least officially) install a CAS OS on a non-CAS calculator and vice versa.

In the hardware, the difference between CAS and non-CAS is using two separate chips:

• the NAND chip
• the ASIC chip

Each of these chips contains a code identifying the calculator as CAS or non-CAS, and these codes are verified and compared at various times:

• by the Boot2 when a new OS is being received and installed
• by the Boot2 each time the OS is being launched
• by the installed OS when a new OS is being received and installed

However Nlaunch, the third party OS launcher released last year exploits a flaw in the Boot2 1.4 to remove the first two checks above, letting you install and run any TI-Nspire OS, and among other CAS OSes on non-CAS calculators.

Intended or not, this attack against the TI business model seems to have greatly displeased. For the the last few months, we've been stroke on all sides by a number of new various protections on the new hardware and software versions of the TI-Nspire.

In a Previous news, we just spotted a new additional protection in the new TI-Nspire OS 3.6 . Indeed, if the CAS version is installed on non-CAS calculator with the help of Nlaunch, the OS just freezes upon startup on the grey screen. So it seems now that once launched, the OS checks the CAS / non-CAS codes one more time in the NAND and ASIC chips.



And what happens when a worker doesn't fully conform to the original plan of the architect-engineer? Quite often the building finally collapses...

With all these protections systematically added around mindlessly (aparently) in the last months and violating the original security model, I was fearing that TI might en up bricking some TI-Nspire... and unfortunately, I was right!



Before the release of the first TI-Nspire, the TI-Nspire ClickPad for back to school 2007, Texas Instruments freely distributed numbers of prototypes during the 2006-2007 schoolyear. I do not know what their lucky owners told TI, but I guess they didn'r really appreciate the gift as many of them rushed to resell it online after the release of TI-Nspire, but of course with a price similar to the production models one. A trained eye will notice several small differences, but the only one common to all prototypes is the mention of an 'EVT', 'DVT' or 'PVT' code in the serial number on the back.

Until the release of color TI-Nspire CX for back to school 2011, online resale shops have been flooded with prototypes apparently very similar with the production models. But even if we put aside the dubious morality of this behaviour, it was nothing more than a monstrous scam! Indeed, prototypes Boot1 and Boot2 validated the signatures with the development keys and not the production ones. As a result:

• These prototypes refused to install any OS released on the official TI website. And As TI doesn't release development OSes it was impossible for you to update the prototypes which remained stuck on old 1.1 and 1.2 versions!
• If you had the bad idea to remove the OS via the maintenance menu, your prototype became unusable because no released OS could be installed on it! >:(

Fortunately, TI-Planet has taken this cause to heart and tried its best to repair the scams you experienced.

• We began first by recovering several functional prototypes from which we could extract some development OSes, allowing you to repair prototypes which had their OS removed! ;D
  
• Then, we noticed on these prototypes that the NOR chip hosting Boot1 was not write-protected. After many months of hard work, we finally proposed you a tutorial based on a Boot1 reflashing in order to transform your TI-Nspire ClickPad DVT prototypes into production models, allowing you to finally install the latest production OSes available at ti.com! ;D

However, the ASIC chip on TI-Nspire ClickPad DVT prototypes doesn't include the non-CAS / CAS identification code. The NAND chip being flashable, a simple modification of its CAS / non-CAS code allows for example the transformation of a non-CAS prototype into a CAS one. This implies that the historical CAS / non-CAS checks are based on differences tests. The code in the ASIC chip being neither CAS nor non-CAS, the test is successful in all cases. ;D

So for months and now years, you've been able to use your TI-Nspire ClickPad DVT prototype as a production model. Unfortunately, you can't anymore. The OS 3.6 freezes at startup on all TI-Nspire ClickPad DVT prototypes, even those whose CAS / non-CAS NAND case has never been changed! :o
So it seems that the new CAS / non-CAS verification on the startup of OS 3.6 was not coded in the same way as the historical verification, using tests of equalities and not differences! In consequences, ASIC verification fails on all these prototypes since there is no CAS or non-CAS code in the ASIC! >:(

This raises some questions about the process of development. Does this error means they do not even test development versions of their new OS on TI-Nspire ClickPad / TouchPad anymore and simply generate them automatically? Or was this change intended to prevent students using six years old non-CAS prototypes turned into CAS ones during exams? It would be really extreme, but not surprising in the context of what we have been experiencing during the last months...

Do you think you simply have to reinstall an earlier version of the OS to repair your prototype? It would have been too easy... Although stuck at the grey screen, the OS 3.6 still has the malice to increase the minimum installable OS version stored in NAND... to 3.6! The only OS that you now have the right to install is the 3.6 which won't work! Your calculator is now unusable... TI just destroyed your rare TI-Nspire ClickPad DVT prototype without warning! >:(
Note that the tool Nlaunch, even if it can't make OS 3.6 work on these prototypes, has the advantage of avoiding their bricking when attempting to use OS 3.6, since it makes Boot2 ignore the minimum installable OS version programmed in NAND.



In addition to the ones you may have purchased online, TI-Planet distributed many of its TI-Nspire ClickPad DVT prototypes, either to developers or to contests winners, and so we have to warn you:
DO NOT INSTALL OS 3.6 ON A TI-NSPIRE CLICKPAD DVT PROTOTYPE - STAY WITH OS 3.2 OR OLDER
There is so far no way to use the OS 3.6 on these prototypes; it is useless to try, even with Nlaunch.


If it's already too late for you, the general idea to ​​repair follows the pattern below:

• if your boot2 is 3.0.1, reflash Boot2 1.4 using an external RS232 interface
• remove the minimum installable OS version using the DowngradeFix tool

Feel free to answer in the TI-Planet topic if needed - we'll try to help everybody.



Let's hope that the TI- Nspire ClickPad DVT prototypes will remain the only victims of the new Texas Instruments behaviour, but it's not impossible to find other similar cases, as a security model designed 6 years ago was suddenly changed.


Source:
http://tiplanet.org/forum/viewtopic.php?t=13280&p=151025&lang=en

In a previous news we were presenting you the new HP-Prime and its rechargeable battery providing a voltage of 3.7 Volts like on the TI-Nspire and TI-84 Plus C Silver Edition, but with a much greater capacity of 1500 mAh and thus an increased energy of 5.55 Wh !
Without any cable unlike on TI models, the HP-Prime rechargeable battery is very easy to install and remove.

According to an information revealed by Tim Wessman from HP on the TI-Planet HP Wiki, the battery coming with the HP-Prime is actually of the same type as those used by the Samsung Galaxy S3 smartphone, which is great a news!
On the one hand, with the existence of generic brands of batteries for this phone, when the time comes you'll be able to buy a HP-Prime replacement battery for cheap!
On the other hand, the most common battery for Samsung Galaxy S3 does provide a compatible voltage of 3.8 Volts, but has a capacity of 2100 mAh and therefore an energy of 7.98 Wh. Thus we can expect from it performances 40% higher than the original HP-Prime battery! The replacement will get you a much better autonomy!

You can even try to opt for more powerful Samsung Galaxy S3 rechargeable batteries, especially in generic brands. Exceeding 2500 mAh, 3000 mAh or even 4000 mAh capacity is possible for an unexpected autonomy! But beware, these batteries are often thicker and thus require some accessories designed for the phone (back cover replacement, special battery cover, battery case extension...). These accessories probably won't be usable with the HP-Prime case. Si if you opt for these powerful batteries, make sure that you buy rechargeable batteries which don't require such accessories.



Source:
http://tiplanet.org/forum/viewtopic.php?t=13143&p=149441&lang=en

For back to school 2010, Texas Instuments did release the TI-Nspire TouchPad with its optional rechargeable battery, the 3.7L1230SP. You got 3.7 Volts for a capacity of 1230 mAh. Thus, a simple multiplication gave you an energy of 4.55 Wh.

For back to school 2011 came the TI-Nspire CX. But the included rechargeable battery, the 3.7L1060SP, was 14% less powerful with a capacity of 1060 mAh and therefore an energy of 3.92 Wh.

For back to school 2012 in China, they were even less lucky. The released TI-Nspire CM was including a much less powerful rechargeable battery, the 3.7L0800SP with a capacity collapsing to 800 mAh and therefore an energy of only 2.96 Wh.

In a previous news, we noted that the new back to school 2013 TI-84 Plus C Silver Edition was including a new rechargeable battery, the 3.7L1200SP, therefore providing 1200 mAh and 4.44 Wh.



In a another previous news, we also warned you against the new back to school 2013 TI-Nspire CX whose hardware revisions I/J/K have been rendered incompatible with the 3.1 versions required by the Ndless 3.1 and Nlaunch jailbreaks.

But finally, there is at least one good news with this new TI-Nspire CX hardware: it's coming with the new 3.7L1200SP rechargeable battery! We're not completely back to the power of the back to school 2010 3.7L1230SP yet, but it's still 13 % more powerful than the old 3.7L1060SP. So you're getting a better rechargeable battery for the same price!

So the choice is now simple when you buy a new TI-Nspire CX:

• hardware revisions A-H for Ndless 3.1 and Nlaunch
• hardware revision I and above for the new improved rechargeable battery

Which one would you choose? ;)



Source:
http://tiplanet.org/forum/viewtopic.php?t=13092&lang=en