Also known as the Business Entry Rule, this exception to the evidentiary rule (which excludes hearsay from a trial) allows buisness records to be admitted if the proper foundation is laid to show the document is reliable.
The Business Records Exception comes from Federal Rule of Evidence 803(6):
The following are not excluded by the hearsay rule, even though the declarant is available as a witness: Records of regularly conducted activity. A memorandum, report, record, or data compilation, in any form, of acts, events, conditions, opinions, or diagnoses, made at or near the time by, or from information transmitted by, a person with knowledge, if kept in the course of a regularly conducted business activity, and if it was the regular practice of that business activity to make the memorandum, report, record or data compilation, all as shown by the testimony of the custodian or other qualified witness, or by certification that complies with Rule 902(11), Rule 902(12), or a statute permitting certification, unless the source of information or the method or circumstances of preparation indicate lack of trustworthiness. The term "business" as used in this paragraph includes business, institution, association, profession, occupation, and calling of every kind, whether or not conducted for profit.