The MOD-SSRY4 is a modular unit with 4 x 250VAC 2A Solid State Relay ports.
The benefit of solid-state relays are their extremely low noise (almost silent) switching, typical 10x faster switching, dramatically longer lifetime and more reliable (no moving parts).

Front of the module has four detachable screw terminal blocks.
Each port features two common pins allowing you to easily loop input voltages across multiple ports for simplified wiring.

Pinout - Top Row

1. Port 1 Common
2. Port 1 Common
3. Port 1 Load
4. Port 2 Common
5. Port 2 Common
6. Port 2 Load

Pinout - Bottom Row

1. Port 3 Common
2. Port 3 Common
3. Port 3 Load
4. Port 4 Common
5. Port 4 Common
6. Port 4 Load

The rear of every module contains a module port, used to connect the module into the modular controller base unit (DIN-MOD4, etc). The pinout for this port is not published.