) Except as otherwise required in subdivision (1) (c) of Section
5102 on scope, no particular form of phrasing is required for a credit. A credit must be in writing and signed by the issuer and a confirmation must be in writing and signed by the confirming bank. A modification of the terms of a credit or confirmation must be signed by the issuer or con- firming bank.
(2) A telegram may be a sufficient signed writing if it identifies its sender by an authorized authentication. The authentication may be in code and the authorized naming of the issuer in an advice of credit is a sufficient signing.