How many controls is too many?
Pcards can record only 20 controls, and some older SI cards have capacity for only 30. Amongst the latter are our SI5 "loaner dibbers". Sometimes people punch a control out of sequence or from another course, so best if their SI card has capacity for at least N+1 controls. Each SI card type has a defined range of SI numbers, so you can scan entries to be forewarned of who has an inadequate card. These number ranges can be found at https://www.sportident.co.uk/information_sheets/SPORTident-CardComparison.PDF
| Name | SI Number | Capacity (controls) |
| SI 5 | 1 - 499,999 | 30 |
| SI 8 | 2,000,000 - 2,999,999 | 30 |
| SI 9 | 1,000,001- 1,999,999 | 50 |
| SI 10 | 7,000,001 - 7,999,999 | 128 |
| SI 11 Flash | 9,000,001 - 9,999,999 | 128 |
| SIAC | 8,000,001 - 8,999,999 | 128 |
| P Card | 4,000,001 - 4,999,999 | 20 |
| Comcard Up | 2,000,001 - 2,999,999 | 30 |
| Comcard Pro | 7,000,001 - 7,999,999 | 128 |