Diameter Index Safety System (DISS)

The Diameter Index Safety System, like the Ohio quick-connect system, is a gas station outlet system used in the hospital setting for the supply of medical gases. DISS connectors are threaded and have a unique diameter for each type of gas to prevent erroneous connection. The system also contains a valve at the outlet/ wall supply side which shuts off gas supply upon disconnection.


Pictures highlighting the unique features of the female (left) and male (right) DISS connectors for nitrous oxide and oxygen


Wall outlet DISS connector for oxygen.

At the outlet/ wall supply side the DISS connectors are also typically color-coded for the gas carried.

The DISS auxiliary oxygen outlet at the back of an anesthesia machine with the 'male' (right) and 'female' (left) connectors.