◇：R ─ Relay output；T ─ Transistor SINK(NPN) output; J ─ Transistor SOURCE (PNP) output
Δ：2 ─ built-in RS232 port；U ─ built-in USB port (non-standard)
◎：AC ─ 100~240VAC power supply; D12 ─ 12VDC power supply; D24 ─ 24VDC power supply
☆：Blank ─ Standard；–C ─ add in RTC
The unmarked frequencies of Digital Input (DI) or Digital Output (DO) are low speed.

B1-8X ☆

8 points 24VDC digital input

B1-8Y ◇☆

8 points relay or transistor output

B1-8XY ◇☆

4 points 24VDC digital input
4 points relay or transistor output

B1-16X ☆

16 points 24VDC digital input

B1-16Y ◇☆

16 points relay or transistor output

B1-16XY ◇☆

8 points 24VDC digital input
8 points relay or transistor output

B1-24XY ◇☆

14 points 24VDC digital input
10 points relay or transistor output

B1-40XY ◇☆

24 points 24VDC digital input
16 points relay or transistor output