How can I keep the data on a KLN89b GPS up to date? I'm looking at a Mooney M20C with a pretty dated panel, but it's airworthy and could be a great opportunity to build some retrac time. The KLN89b GPS is IFR Certified, but is positively ancient. 

There seems to be a convoluted process to keep it up to date. I don't know if the present owner has the cable or the proprietary card reader. I've found some on eBay that seem to be for the KLN94 so I'm not sure if they will work with the KLN89b. 

In my club we have a C172 with a GNS430 that has a fairly straightforward update process. I'm hoping the KLN89b is pretty similar if I get the card reader. I certainly don't want to take the entire GPS out of the aircraft and load it into a docking station every month.

If anyone can share their experience with this unit that would be great.
Thanks Guys. I've contacted the manufacturer and they said that there is an approved cable, only sold by avionics shops, that will connect an old fashioned serial port to the data port on the panel. If I get a USB to serial computer, I may be able to use Windows 10 to install the update. Maybe I'll have to downgrade to Win7.

I asked if there was a published end-of-service date for the unit and they stated that there was not. I also asked if there was a guarantee of future database availability for any period into the future and she said that there was no guarantee, but no plans that she knew of to phase the unit out.