Major differences are shown below.

- AJ65SBTB1-16DT1
<Input specifications>
- Rated input current approx. 5 mA
- ON voltage/ON current 15 VDC or higher/3.0 mA or higher
- OFF voltage/OFF current 3 VDC or lower/0.5 mA or lower
- Input response time 0.2 ms or less

<Output specifications>
- Leakage current at OFF 0.25 mA or lower
- Protection function provided (overload protection, overvoltage protection, overheat protection)

- AJ65SBTB1-16DT2
<Input specifications>
- Rated input current approx. 7 mA
- ON voltage/ON current 14 VDC or higher/3.5 mA or higher
- OFF voltage/OFF current 6 VDC or lower/1.7 mA or lower
- Input response time 1.5 ms or less

<Output specifications>
- Leakage current at OFF 0.1 mA or lower
- Protection function none

For more details, refer to the following databook.
 - Open Field Network CC-Link Compatible Product databook