Subpoena Ad Testificandum: Phone Records, Text Messages, and Third-Party Subpoenas

A subpoena ad testificandum is a legal order compelling a person to appear and provide oral testimony — distinct from a subpoena duces tecum, which compels the production of documents or records. Both types of subpoena serve the discovery process in civil and criminal litigation, but they operate differently. When litigants need to know if they can subpoena text messages, or whether a subpoena phone records request will yield the data they need, the answer depends on the jurisdiction and the specific carrier or service involved.

A subpoena server is the person responsible for delivering the subpoena to the commanded party — service of process is a legally required step without which the subpoena has no effect. A third party subpoena reaches organizations or individuals not named as parties to the lawsuit but who possess relevant records or knowledge.

What Is a Subpoena Ad Testificandum

A subpoena ad testificandum commands a specific person to appear at a deposition, hearing, or trial and give sworn testimony. The document specifies the date, time, and location of the required appearance. Unlike a document subpoena, the subpoena ad testificandum compels the person’s presence rather than the production of physical records.

Courts can quash or modify a subpoena ad testificandum on grounds including:

• Undue hardship or geographic limitation (federal subpoenas are generally limited to 100 miles from the witness’s residence)
• Privileged testimony (attorney-client, doctor-patient, clergy-penitent)
• Fifth Amendment invocation in criminal proceedings

Can You Subpoena Text Messages

Parties frequently ask whether they can subpoena text messages, and the answer is yes — with limitations. There are two paths: subpoenaing the content of text messages stored on a person’s device (through a device examination order), or serving a third party subpoena on the mobile carrier for stored records.

Carriers retain text message metadata (date, time, sender, recipient) for varying periods — typically 18 months to 7 years. However, the content of text messages is retained by most major carriers for far shorter periods, if at all. Under the Stored Communications Act, obtaining message content from a carrier requires either a warrant (in criminal cases) or a civil subpoena combined with notice to the account holder.

When asking can you subpoena text messages in a civil case, the practical approach is to subpoena the opposing party’s phone directly for device examination or seek a court order compelling production of relevant messages from the party’s own device.

Subpoena Phone Records

A subpoena phone records request directed to a carrier typically yields call detail records: numbers called, call duration, timestamps, and tower location data for cellular calls. This data is more routinely available than text message content. Carriers respond to subpoena phone records requests within the time specified in the subpoena, typically 14-30 days, with a certification of records authenticity.

Call records obtained through a subpoena phone records process are admissible as business records in most jurisdictions when accompanied by a proper custodian certification. The records do not reveal the content of conversations — only that the calls occurred.

Subpoena Server: Service of Process Requirements

A subpoena server must deliver the subpoena through legally recognized means. For individuals, personal service — handing the document directly to the named person — is the most reliable method and satisfies requirements in virtually all jurisdictions. For entities, service on a registered agent, officer, or managing member typically satisfies legal requirements.

The subpoena server must complete a proof of service (also called affidavit of service) documenting the date, time, location, and manner of service and the name of the person served. This document becomes part of the court record and proves the subpoena was properly delivered.

Third Party Subpoena Compliance

A third party subpoena reaches organizations not involved in the litigation — banks, employers, medical providers, or phone carriers. Recipients of a third party subpoena have the right to seek a protective order limiting the scope of production, particularly when the subpoena is overly broad or requests confidential information about third parties not involved in the case. Third-party recipients should consult counsel before either complying or objecting to a third party subpoena, as both the failure to comply and improper disclosure of protected information can create liability.