If I take a telephone order and enter it using the 'New Order' tab in SellerDeck,is..

[KB]

If I take a telephone order and enter it using the 'New Order' tab in SellerDeck, is the payment processed by our PSP if we choose that payment option?

Only SellerDeck Payments is integrated to automatically connect to the Payment Service Providers (PSPs) servers to process the payment when taking an offline order. For all other PSPs you will have to manually connect to your online account to process the payment or put it through your PDQ machine.