I was reading this page and this comment and explanation was confusing me.
Further comments here:Start out right and don't use the hose-barb fittings. For the same price you can get threaded fittings which allow you to very easily expand your kegs to service both Coke and Pepsi (pin-lock and ball-lock). It costs a bit more because you then need fittings for your hoses, but in our opinion it's worth it.
The premise that a threaded fitting system would allow a hybrid system that could use both pin and ball lock kegs sounds ideal, however I'm failing to see how a threaded system could do this and not a barbed. I'm betting there is a very good reason they are saying this, but I just can't make it out and would appreciate anyones attempt to shed some light on this for me.The first thing you will need is the fittings appropriate for your type of keg. The fittings have a large female socket at one end which fits down over the corresponding fitting on the top of the keg. At the top of the socket, sticking diagonally upwards out of the side, is either a 3/8" OD (outer diameter) hose barb, or better yet, a 3/8" OD threaded male compression fitting. We strongly encourage you to start off by getting the threaded fittings, since this will allow you to run a hybrid system of Coke and Pepsi kegs. The fittings themselves are the same price either way, though you may have to special order the threaded ones since some brew shops don't seem to carry them. Also, you'll have to purchase the corresponding female compression fitting which attaches to the end of the hose that you'll be connecting to it, so it is a bit more expensive to get going. But even if you don't ever want to mix kegs in your own setup, it's useful to have for special circumstances. For example, you may someday find yourself throwing a party, and a brewing friend of yours wants to bring a keg along, but she has the opposite setup as you do. If you have the compression fittings, you'll find it extremely easy to accommodate your friend's kegs. But I guarantee you'll kick yourself the moment you find a really good price on the opposite type of kegs than they ones you currently have on your system, and therefore have to purchase all new fittings for all of your kegs in order to run a hybrid system. Trust us on this one, we've been there. You can actually set up a hybrid system with the hose-barb fittings, but it isn't nearly as versatile as it would be using the compression fittings. Basically you have to split your gas line in two with a T fitting, then dedicate one half to Pepsi, and the other half to Coke. You'll also have to maintain two completely separate serving line systems, which can be a real pain if you want good taps on your system because you'll have to dedicate one tap to ball-lock, and the other to pin-lock.
TIA