Through which two configuration elements off-net calls routed in inbound and outbound direction respectively?

Route lists sit above route groups in the outbound hierarchy and represent the outbound layer, while outgoing CSS is not the designated mechanism for inbound call direction control in CUCM.

The inbound CSS configured on a gateway or SIP trunk determines which partitions and route patterns an arriving off-net call can match, controlling inbound routing direction. Route groups are collections of gateways used in the outbound routing chain - referenced by route lists and route patterns - to direct calls out to the PSTN, making them the outbound routing element.

Device pools are administrative constructs grouping devices by common settings such as region and date/time group, and they do not perform directional call routing.

Route patterns match dialed digit strings to initiate outbound routing but are not a directional control element for inbound off-net calls arriving at the system.