In the UK, quite a few IntelliVue MX series patient monitors and associated equipment is being disposed of, presumably due to reaching end of service life. They are relatively modern and sophisticated pieces of equipment though, and I managed to get an Mx800 pretty cheaply (£80) to have a play. It seems the MX400/500/700/800 are all very similar in software, the 400/500 is smaller and more portable and can have a patient module docked directly into the rear, the 700/800 have larger screens and are intended for fixed operation because they need a separate patient module and don't have built-in battery backup.
The patient connectivity is through 2x MSL ("Measurement Server Link") connectors, which is connected to either a patient module (such as an M3001A), a module rack, or an IntelliVue X2 (which is a self-contained patient monitor in itself). When connected to an X2 the X2 goes into a secondary mode (screen off) and just sends its measurements to the MX.
The X2s are also being disposed of here, and I bought a few of them very cheaply. All seemed to work, although the battery in one refused to charge.
MSL Link
The MSL is a highly-proprietary connector used only on Philips devices. I got a hint of how it works due to there being an ethernet adapter cable available for firmware upgrades.
I disassembled an X2 to have a look at the connections. There's a handy service manual available, but please do take note of the warning that the display ribbon cable is quite short. When you remove the front cover you must do so very carefully because it's very easy to damage the ribbon connectors. I slightly damaged one of mine, luckily a scrap one I didn't mine sacrificing!
Upon slicing an MSL cable open I could see a bunch of twisted pair wires, and some thicker power wires.
I then disassembled an X2 and could see an ethernet transformer, meaning I could identify two of the pairs as ethernet. I then connected these to an old 10/100 ethernet switch and got a sync and connection! I used Wireshark to monitor the data between the X2 and Intellivue, however I couldn't immediately spot anything interesting. Here is a table of the wire colours and what I could spot:
| Colour | Type | Function |
|---|---|---|
| Purple | Data | Ethernet |
| Purple/white | Data | Ethernet |
| Green | Data | Ethernet |
| Green/white | Data | Ethernet |
| Brown | Data | Unknown data, serial measurement data I think |
| Brown/white | Data | (as above) |
| Grey | ? | ? Square wave from MX (power sync I think) |
| Grey/white | ? | N/C? |
| Blue | ? | Serial from MX? RS-422? |
| Blue/white | ? | (as above) |
| Red | Power | Power ~56V DC |
| Red/white | Power | Charge? |
| Black | Power | Power? |
| Black/white | Power | Charge? |
| Green/black | Power? | ? Power sync data? |
IntelliVue X2 Battery
As mentioned, one battery didn't charge when connected to the MX, so I had a look to see about refurbishing it.
The front panel was already loose, it seems to clip on, but the clips on mine fell apart. I think sliding it down would 'unlock' the whole battery.
The sides then came away quite easily, revealing 3x 18650 cells and a BMS on the top. The cells are attached together using a small bead of hot glue.
Refurbishing would seem to be pretty easy - desolder the BMS leads, glue together 3x new cells and either spot-weld them together, or buy pre-tagged cells and solder the tags together. Then glue/tape the casing back together (or clip it, if you managed to remove it intact)
Update: I bought 3x new 18650 cells, charged them fully, spot-welded them together and soldered them onto the BMS, however the BMS light flashes empty.