I agree that arbitration should be compelled with regard to the letter dated December 21, 1981, which covered the last contract. However, arbitration should have been stayed with regard to the first three contracts covered by the letter dated January 11, 1982. The parties do not dispute the fact that the contracts evidence a transaction involving interstate commerce and are thus governed by the Federal Arbitration Act ([FAA] US Code, tit 9, § 1 et seq.). The State courts are thus required to enforce Federal substantive law (Matter of Rederi [Dow Chem. Co.], 25 NY2d 576, 579). The FAA overrides inconsistent provisions of the arbitration acts of the States (supra, at p 583). The FAA does not have any provisions governing the manner in which a demand for arbitration should be served. In the absence of any such provision, CPLR 7503 (subd [c]) *717must govern. That statute requires one party to serve the other party with the demand for arbitration (cf. Matter of Matarasso [Continental Cas. Co.], 56 NY2d 264, 267). Since Campus served the demand upon the attorney for Initial Trends, Inc., rather than upon Initial Trends itself, the demand is null and void. Hence, we lack jurisdiction over the dispute. Therefore, Initial’s petition should be granted only to the extent of staying arbitration with regard to the first three contracts.