Note
I learned something new about SI just now. So up here in BC, we have a province wide SI numbering scheme so that we can share units between events without any issues. Great plan, works awesome all the time, we give units to other clubs for major events, and they reciprocate. Last piece of pertinent background info: we just got 10 new units for the Revelstoke branch of our club, and are repurposing 10 other units from Kamloops to Revelstoke.
Here's the rub: the normal opporating range of SI codes is 1 - 255. Those of you who know binary will know why 256 is not in the normal range. While newer SI (everything after SI 5) cards will be just fine above 256 (they're good until up to ... you guessed it ... 1023). My new Revelstoke units go above 255, all the way up to 266 in fact. I'm not sure how many people still use SI 5 cards, hopefully not many. I know about 1/6 of our rental club SIs are still SI5, but they are starting to get a bit wonky and I want to have them retired anyways to be honest. For BCOC this year, I think I'm going to just have to give a free SI rental to anyone who registers with an SI 5 number.