Where can I get one?
Thanks
The easiest place is IFI.
Scroll down or search for DB15
If you’re planning on making a competition port dongle or a custom switchboard for your OI, don’t bother with that. There are better things to use. If you just need a cable, you can get it there.
If you find an electronics store frequented by hobbyists
and repair people, you will find the connectors and cables
that you seek. They are called d-sub connectors. You
get the connector, the back shell, the crimp pins, and 15
conductor cable at the same store. You want the male
connector and pins.
Check your phone book for electronics stores and call them
and ask if they have dsub connectors and tooling.
We use the ss109 aircraft rated version, ordered from www.steinair.com.
What you are likely to find at a local store is the commercial stamped
pin version, but it will do just fine.
Eugene
These connectors are called “DB-15”, or “D-Sub 15” connectors.
Your local connector store should have them, as they are very common. Maybe even RadioShack. Worst comes to worst, you can cut off the connector from something else. You COULD order from digikey, but we ship in 3 days, so that would only give you about a day to build whatever you are trying to build.
You can use just regular wire. (24,26 gauge… Stranded telephone wire)
Jacob
I think the quickest way is to buy a solder cup DB15 from radioshack and use a multiconductor wire like a cat5 cable.
hope this helps.
I did not find any 15 pin connectors at Radio Shack…they have been obsolete for a while.
Were you referring to the connectors, or Radio Shack? 
Sorry for the late reply…
I usually order most of our Teams “electronic” stuff from online mail order vendors. Mainly because our local RadioShack has done away with or stopped carrying the components we use. The DB-15 solder cup for example. I tend to use Jameco when possible and try to order in advance of the season for common items.
DB-15 Solder Cup:
http://www.jameco.com/webapp/wcs/stores/servlet/ProductDisplay?langId=-1&storeId=10001&catalogId=10001&productId=15035
Housing:
http://www.jameco.com/webapp/wcs/stores/servlet/ProductDisplay?langId=-1&storeId=10001&catalogId=10001&productId=15019
Wire 15 Leads:
http://www.jameco.com/webapp/wcs/stores/servlet/ProductDisplay?langId=-1&storeId=10001&catalogId=10001&productId=644455
go to l-com.com, they have everything in electronic
Radio Shack only sells the *High-Density *DE-15 connectors, which are used for VGA video for example. Standard DA-15 connectors are not carried by RS.
Aside from Jameco, also check DigiKey, Mouser and Circuit Specialists.
Don
our local radio shack has standard solder on DB-15 connectors
Typically larger RadioShacks in smaller communities have more ‘parts’ and less consumer electronics. I don’t know what your RadioShack is like, but most of ours around here are electronic toy sale centers, as opposed to part centers. It sounds like yours is more like the one by my summer home in Maine, in a very rural community. The guy there sells everything from connectors to albums, and high-end and low-end speaker systems that he bought in the 70s! 
Jacob
LOL! I used to hang out in Radio Shack in the good old days (mid 1970’s), when I was 12, and help the customers (I knew more about electronics than most of the sales people). It was almost a real electronics store back then. They used to have walls and walls of parts: Now they have a few parts in drawers, and a few on the wall. I have more Radio Shack electronics parts than just about any Radio shack store does these days. Now they are mostly just an overpriced cell phone store (Though I occasionally drop in for old time’s sake). 
One of my saddest days was when they discontinued the Radio Shack catalog. I looked forward to it every year, and read every page as soon as it came out. I still have every year from the mid 70’s to the end. (Maybe this post should go in the “I am a geek because …” thread.)
PS: If you want to see how to connect to the OI in style, see the Team 116 OI adapter board on my web site via my link below, and in the thread about it here.
super easy, go here:
http://www.action-electronics.com/computercables.htm?zoom_highlight=db15#Db15
Order this part, a male to male 15 pin cable. S-15MM-10
It is less than $ 11
then cut it in half and then you will have TWO cables. and wire the end into your custom box and save the hassle of fabricating the OI end of the cable.
We get a lot of small electronics parts from these guys:
Marlin P Jones