Right, the definition I'm using is being able to input the typical 31250 Hz UART current loop into the cartridge with minimal effort, as that would be one of the two things people would actually be interested in using for practical purposes. (The other one being MIDI over USB.) Additionally, even if you set up MIDI over V.22bis, I believe the Gameboy CPU would have to poll the cartridge periodically to see if a UART transfer had started, whereas the game link port can create an interrupt.

I think that depends on how loosely you are willing to define 'MIDI'.

Surely there would be somewhere on the PCB to tap the data signal before digital-to-analogue conversion, or even just take the analogue modem signal feed it into an audio input on the other end to convert it back to digital using a software solution like minimodem.

MIDI over a modem connection was done 20 years ago, and more than once.

Wow this is still pretty cool.

ooh, I have one of those
interesting..

someone make a multiplayer game with modem function please

Onboard MIDI, nope, sorry. There are a couple of caveats about using this cart as a flashcart, but it could be a moderately useful cart for that purpose. ROMs would need to modified to work with this cart and there's no SRAM to save data in, only flash that is shared with the program memory. I don't think anything can currently use that as save data.

...some more work has been done on the Shark MX Modem cart:

http://www.bennvenn.com/Reprogramming_the_Shark_MX3.htm

and they are still available on eBay!

$5.95 for a 256kb flash cart with a serial port onboard (MIDI possibilities?) could be a beautiful thing!

...a possible starting point?

http://ewen.mcneill.gen.nz/programs/cpc/ansiterm/

Obviously, but if a simple dial-up terminal ROM could be made then you would just need to find an ISP that still offers dial-up Unix shell access, like:

http://sdf.org/?dialup

and maybe use a PS/2 keyboard mod for text input?

or see if any dial-up bulletin board systems still exist in your area? or setup a new one?

or if somebody wanted to act as a host then it's fairly straight forward to setup a dial-in server in Linux to share your internet connection:

http://www.howtoforge.com/linux_dialin_server
http://derrick-caluag.blogspot.com.au/2 … linux.html

and then you could do something really nerdy like use Twitter or Facebook from the command line:

http://www.floodgap.com/software/ttytter/
http://fbcmd.dtompkins.com/

Apparently the cart requires activation before it will do anything making it fairly useless without any modification:

"For those of you considering the purchase of a Shark MX, be advised that since the sale of Gameshark (from Interact to Madcatz), there is no longer any support for this device, nor the proprietary email service (Gameshark BBS). The toll free# on the 30min activation card has been disconnected, and Madcatz has been of little assistance. (Apparently Madcatz only purchased the website and software rights to Gameshark, and not the "technology" portion.)

Without the MX cart first being "activated" with a factory issued REG CODE (via toll free#), the cart will not function at all, rendering it completely useless. I find it odd that Interact would have locked up the entire cart in this manner, as the PDA functions are not in any way linked to the email functions (ie, address book not linked to email composer).

If you're a collector of odds/ends GB carts, it would be a unique buy. It is a cool gizmo. Don't plan on any serious usage of the device though. Good luck with your purchase. 7/2003"

Did some googling, came up with this:

since it's compatible with the cgb, it can't use the fifth channel. that one was only in the original DMG (i think they even removed it from the pocket.. but don't know for sure)

It has it's own speaker added, and probably uses the gameboy to trigger the sounds.
which seems funny, but not really usefull.

Still interesting tho.

Doesn't Pocket Voice use the 5th sound channel? Also worth checking out for the hardware possibilities.

I remember reading a big article about the Shark MX when I was a kid. It is cool that they found a way to do that, but I'm not sure if the service itself is still functional.

Regardless, if you could reverse engineer the game boy modem and find a way to do network play, that could be cool…

That would be hilariously awesome, sync it to our cybiko wireless and really fly!

pretty cool!  good find

Imma get me one.

Found some info on the modem cart:

http://www.oocities.org/grinara/

...looks like it is reprogrammable, I think it'd be really neat to have a simple dial-up terminal on it - maybe hook it up to a mobile phone or start some GameBoy bulletin board systems?! Especially since that seller has 4,291 of them for sale at $5.95 each!!