Originally posted at http://pspvault.com

The other day, I was thinking to myself, "wouldn't it be nice if I could use some of my older Memory Sticks with my PSP? I mean I have this 256MB stick and a 64MB stick...seems like they're just being wasted..."
And so my search began. I was led to this page:
http://www.clubsonyericsson.com/en/products_uaccesories_armmsjacket.shtml

If you for some reason are unable to reach that page, it is an adapter called the "A.R.M. Memory Stick Jacket." This jacket, originally intended to be used with Sony Ericsson's P800 mobile phone, takes a backdoor approach to using Memory Sticks in the P800's Memory Stick Duo slot. Apparently when the P800 there was enough demand to drive a company to create a product like this.

"Hey!" I thought. "Something like that might work for the PSP!" But I didn't really feel like paying 80 Euros for something like this; I just wanted the added convenience (which frankly, wouldn't be much) of adding Memory Stick support to a device intended to only accept Memory Stick Duo. So I looked around for a bit, and found this page:
http://www.expansys-usa.com/product.asp?code=P800_MSEXP
(note that PSP-Vault does not necessarily endorse this vendor; the link is provided only for your convenience. Shop around!)

"$30 is more like it," I said. So I went ahead and ordered one on Sunday night. Sure enough, I come home today, and here it is. I opened the package to find this inside:

The A.R.M. Memory Stick Jacket is admittedly a ripoff at $30. It consists of a small interface for the Memory Stick Duo slot, and you plug the other end of the interface into the circuit board of the Memory Stick slot interface. In other words, the A.R.M. Memory Stick Jacket provides a sort of "bridge" between the two formats. It appears to be very simple in construction, but I don't know the first thing about electrical engineering, so don't hold me to it. Since the Memory Stick Jacket is intended to be used with a Sony Ericsson P800, the Memory Stick slot circuit board is mounted in plastic casing. Consequently, this casing supposedly acts as a replacement for the conventional P800 battery cover. I guess it has a streamlined look on the P800, but since I don't own this phone, I don't really care. I'll be using it with the PSP. The product works as advertised, however, so I can't complain too much.

Before we continue, I'd just like to clarify the difference between Memory Stick and Memory Stick Duo for those that don't know. As far as I can tell, there is technically no difference between the two formats (unless you count data density as technical). The difference lies in their form factors, and their form factor alones. In the following picture, I am pointing to a Memory Stick. For comparison purposes, I have placed a Memory Stick Duo immediately below it.

As I mentioned earlier, the A.R.M. Memory Stick Jacket consists of two parts. Let's take a look at the Memory Stick slot portion first.

And here is a Memory Stick being inserted into its Memory Stick slot:

The Memory Stick slot portion is simple. You have a slot for your normal Memory Stick, then a place to plug in the cable that runs from the Memory Stick Duo adapter. We'll get into how to plug in the adapter in a few minutes here. But first, let's take a look at the A.R.M. Memory Stick Jacket's other component, the Memory Stick Duo adapter.

One one end of the cable is an adapter the exact same size as any other Memory Stick Duo. Or at least that's what I thought at first -- getting the thing to fit inside of my PSP was a battle. It turns out there is a small layer of plastic that needed to be removed (the Memory Stick Jacket does not include an instruction manual). I even had to steal my girlfriend's nail file and file down a couple ends that stuck out.
On the other end of the cable is a connector that runs to the Memory Stick slot portion of the Memory Stick Jaket.

So let's go ahead and insert the Memory Stick Duo adapter into the PSP (or try to). It doesn't fit very well, but playing with it for a few minutes should get it in there. Once you've filed down the sharper edges and removed the layer of plastic, you should be good to go.

I think it is important to note that the Memory Stick Duo door can still close while the adapter is inserted. Not too big a deal seeing as how this is definitely not a permanent solution, but this does make things slightly more acceptable.

Now that you have your Memory Stick Duo adapter inserted in your PSP, it's time to connect the adapter to the Memory Stick slot portion of the A.R.M. Jacket. It took me a minute to figure this out, but the connector uses one of those "locking" mechanisms to hold itself in place. You'll need to push outwards on the black plastic, insert the connector in the orifice, then push the black plastic back in to lock it in place. I guess I like this more, as it makes things slightly more sturdy.

That's all there is to connecting the A.R.M. Jacket. I inserted a Memory Stick into the slot of the A.R.M. Jacket, and look what I saw (note the Memory Stick LED):

"Whoa!" I thought. "It works!" Sure enough, I was immediately able to browse some digital camera pictures I had stored on that Memory Stick from the PSP.

One thing that irked me, however, was whether or not Memory Stick PRO would work using this contraption. Why would I care about something like that? Simple. Memory Stick PRO goes up to 4GB; for now, the largest Memory Stick PRO Duo cards I know of are 2GB. Memory Stick PRO has traditionally been "one step ahead" of Memory Stick PRO Duo in terms of capacity. I'm also willing to bet that a Memory Stick PRO with a capacity equal to that of a Memory Stick PRO Duo would be considerably cheaper. Don't ask me how much cheaper, but I'll assume this is the case.

Unfortunately, I do not own any actual Memory Stick PRO cards to test this. So I got creative. I do own a Memory Stick PRO Duo, which thankfully included a "Memory Stick Adapter." The Memory Stick Adapter allows you to use a Memory Stick Duo card in a normal Memory Stick slot. This is getting sort of confusing. Here's a little outline of where we stand:

PSP > Memory Stick Duo Adapter > A.R.M. Jacket > Memory Stick Adapter > Memory Stick Duo

Got all that? Basically, I sidestepped my lack of a Memory Stick Duo by using a Memory Stick PRO Duo inserted in the included adapter. This is the best I can do for experimentation right now. Here is the Memory Stick PRO Duo being inserted in the adapter.

Let's go ahead and insert it in the A.R.M. Jacket, too:

Lo and behold, the PSP reads the card correctly (note the 79MB free on the following screen):

Yes, you can indeed play movies from the cards.

Now that we know the PSP does in fact support conventional Memory Sticks, a few questions come to mind:

• Does this mean I can use the Memory Stick Camera?
• Does this mean I can use the Memory Stick Bluetooth Adapter?
• Can I really use a 4GB Memory Stick in my PSP? Wouldn't that be like....12 hours of video, or crapload of music?
• Couldn't I get something like a Memory Stick to CompactFlash adapter, and be able to access up to 12GB of stuff from my PSP?

In all honesty, I don't know the answer to any of these questions. I do know for fact, though, that use of the Memory Stick Camera and Memory Stick Bluetooth Adapter requires software-based support; these two products were originally intended for use in Sony's Clie line of PDAs that run PalmOS5. Furthermore, the PSP already provides a USB port -- it wouldn't make much sense for Sony to use Memory Stick I/O when they could just as easily use USB (and probably allow the final product to be cheaper).

As far as using a 4GB Memory Stick is concerned, well, I can't say. Maybe if Sony would send me a review unit I could test it out :)

Regarding the Memory Stick to CF (or other media) adapters, these are also up in the air. I have seen adapters that go FROM Memory Stick TO CompactFlash, but I have not seen adapters that go FROM CompactFlash TO Memory Stick. I'll need to do some more searching; if you come across something like this, please let me know. Given the huge capacity and cost advantage CompactFlash has over Memory Stick, it could provide a way for PSP gamers to store massive amounts of data.

I'd also like to say that this whole A.R.M. Memory Stick Jacket deal is just sort of "proof of concept." Given the plastic casing in which the Memory Stick slot is entombed, it is far from transportable or even attractive. Hopefully, Sony or another company will come along with an "official" adapter for those of us stuck with legacy Memory Sticks.