1) Is the SCM820-DB25 supplied with audio interface cables?
2) Does the DB-25 interface cable have to be a Shure model?
1) No. The cable must be purchased separately.
2) It does not have to be a cable sold by Shure. Make certain it is an ANALOG DB-25 cable. A digital DB-25 cable can have a different wiring scheme that is incompatible with the SCM820-DB25.