Does the OPUS card use close physical proximity or WiFi networks to make payments?
OPUS card: OPUS is a rechargeable, contactless stored-value smart card using the Calypso Standard and is used by major public transit operators in Greater Montreal and Quebec City, Quebec, Canada. Contactless payment:  Contactless payments are made in close physical proximity, unlike mobile payments which use broad-area cellular or WiFi networks and do not involve close physical proximity.
close physical proximity