(1) A promissory note is an unconditional promise in writing made by one person to another signed by the maker, engaging to pay, on demand or at a fixed or determinable future time, a sum certain in money, to, or to the order of, a specified person or to bearer.
(2) An instrument in the form of a note payable to maker's order is not a note within the meaning of this section unless and until it is indorsed by the maker.
(3) A note is not invalid by reason only that it contains also a pledge of collateral security with authority to sell or dispose thereof.
(4) A note which is, or on the face of it purports to be, both made and payable within the British Islands is an inland note. Any other note is a foreign note.