The primary differences between the iO64 and iO1000 involve device capacity, notification circuit (NAC) configuration, and expansion options.
| Feature | iO64 | iO1000 |
|---|---|---|
| Max Addresses | 64 total [1](Page 6) | 1,000 (250 per loop) [1](Page 1) |
| Loop Expansion | None (Fixed at 1 loop) [1](Page 2) | Expandable to 4 loops [1](Page 6) |
| Standard NACs | 2 Class B [1](Page 1) | 4 Class A or Class B [1](Page 1) |
| Total NAC Power | 3.75 A [1](Page 6) | 6.0 A [1](Page 6) |
| Max T-Taps | 63 [1](Page 6) | 124 per loop [1](Page 6) |
| Internal Battery | Up to two 10 Ah [1](Page 243) | Up to two 18 Ah [1](Page 243) |
The iO64 requires an optional SA-CLA module to achieve Class A NAC wiring, whereas the iO1000 is "Class A Ready" [1](Page 6). Additionally, the iO1000 supports the D16L-iO LED Display Expander for zone annunciation, which is not compatible with the iO64 [1](Page 6).
