“Trap and trace” sounds like a hidden wire from a crime show, but South Dakota law treats it as a narrower kind of communication tracing. It is usually not about hearing a phone call or reading a message. It is about the outside trail of a communication. A pen register watches what goes out. A trap-and-trace device watches what comes in. The words stay behind the door, but the tracks in the snow around the door can still tell a story.
South Dakota has its own state rules for pen registers and trap-and-trace devices in South Dakota Codified Laws 23A-35A-22 through 23A-35A-34. Those sections sit in the chapter on interception of wire, electronic, and oral communications. They cover the court-order rule, who may apply, what the application must say, when a judge issues the order, how long the order may last, sealing, nondisclosure, provider help, compensation, immunity, and good-faith protection. South Dakota also has a separate tracking-device warrant rule, which should not be mixed up with trap-and-trace law.
High-end privacy and record-security picks: a serious home or office setup can pass $2,000 once it includes a premium shredder, fire-resistant safe, hardware security keys, locked file storage, secure router, and encrypted backup drive. Good Amazon starting points include a high-security paper shredder, a fireproof document safe, YubiKey security keys, a Wi-Fi 6 router with security features, and an encrypted external hard drive. These products can help guard files and accounts from ordinary misuse, but they do not stop a valid court order.
What a Pen Register Does
South Dakota defines a pen register as a device that records or decodes electronic or other impulses that identify numbers dialed or otherwise sent on the communication system where the device is attached.
In plain English, a pen register asks: who did this line or system reach out to? It looks at outgoing number data. It should not, by itself, reveal the words spoken during a call or the body of a message.
Think of a pen register as a person watching outgoing envelopes at a counter. They can see the address on the outside and the time the envelope leaves. They cannot open it and read the letter. Still, a stack of envelopes can show habits, ties, and repeated contact.
What a Trap-and-Trace Device Does
A trap-and-trace device works in the other direction. South Dakota defines it as a device that captures incoming electronic or other impulses that identify the originating number of an instrument or device from which a wire or electronic communication was sent.
In plain English, it asks: who reached in? It can help identify the origin of incoming communications. It traces the path toward the target line or device, not the words inside the call or message.
Picture a farmhouse lane after fresh snow. A pen register studies the tracks leaving the house. A trap-and-trace device studies the tracks coming toward it. Neither one opens the door and listens to the people inside.
South Dakota’s Main Statutes
The key South Dakota sections are SDCL 23A-35A-22 through 23A-35A-34. Section 23A-35A-22 gives the main ban. Section 23A-35A-23 deals with provider activity. Sections 23A-35A-24 and 23A-35A-25 cover applications. Sections 23A-35A-26 through 23A-35A-29 cover the court order, order contents, time limits, sealing, and nondisclosure.
Sections 23A-35A-30 through 23A-35A-34 then cover assistance, results from trap-and-trace devices, reasonable payment, immunity for helpers, and good-faith reliance.
The rules are not long, but they are direct. A person may not use this kind of tracing device first and ask legal questions later. The court-order path is the center of the law.
The General Ban
South Dakota law says no person may install or use a pen register or trap-and-trace device without first getting a court order under SDCL 23A-35A-27, unless the listed statutory path applies.
A violation is a Class 1 misdemeanor. That label matters because the rule reaches private people as well as government actors. A spouse, roommate, landlord, employer, neighbor, private investigator, or business rival should not try to trace someone else’s calls or communication traffic on their own.
Suspicion is not a court order. A breakup is not a court order. Paying a phone bill may not be enough. A secret trace can become a snare for the person who set it.
Provider Activity
South Dakota’s pen-register definition excludes devices used by a provider or customer of wire communication service for billing, recording as an incident to billing, cost accounting, or similar business purposes in the ordinary course of business.
That means an ordinary provider billing system is not treated the same as an investigative pen register. Phone companies and communication providers need records to run service, send bills, solve abuse, and manage systems.
That business lane should not be confused with private snooping. A provider keeping billing records is one thing. A private person secretly setting up tracing on another person’s line or account is another.
Who May Apply for an Order?
An investigative or law enforcement officer may apply for an order or for an extension of an order. The application goes to a judge of competent jurisdiction, which South Dakota defines as a circuit court judge.
The application must be in writing. It must be made under oath or an equivalent affirmation. That sworn form matters because the officer is asking a judge to approve live tracing of communication data.
The application is tied to a criminal investigation. This is not a civil lawsuit shortcut, a workplace shortcut, or a private dispute shortcut.
What the Application Must Say
The application must identify the law enforcement or investigative officer making the request. It must also identify the law enforcement agency conducting the investigation.
The applicant must certify that the information likely to be obtained is relevant to an ongoing criminal investigation being conducted by that agency.
That is the South Dakota gate. The request does not have to show probable cause in the same way a search warrant often does. The statute uses a relevance certification for pen registers and trap-and-trace devices. That lower gate exists because the order is aimed at outside communication data, not the message itself.
The Ex Parte Order
When the application meets the statute, the court enters an ex parte order. “Ex parte” means the person whose line or device is involved does not appear before the judge during the request.
That may feel one-sided, but these orders are investigative. Advance notice could warn the subject of the investigation. The judge still acts as the gate, and the order still has limits.
The court may authorize installation and use within the court’s jurisdiction if the judge finds that the officer has certified relevance to an ongoing criminal investigation.
What the Order Must Include
The order must identify, if known, the person whose name is listed on the telephone line or electronic communication device where the pen register or trap-and-trace device will be attached.
The order must identify, if known, the person who is the subject of the criminal investigation. It must also state the number and, if known, the physical location of the phone line or electronic communication device.
For a trap-and-trace device, the order must include geographic limits. It must also state the offense to which the information likely to be obtained relates. Upon request, the order must direct furnishing of information, facilities, and technical help needed for installation.
How Long the Order Can Last
A South Dakota order may authorize installation and use for no more than 60 days. If law enforcement needs more time, an extension may be granted.
An extension requires another application and the same judicial finding required for the first order. The extension may also last no more than 60 days.
The dates matter. A lawyer may compare the order date, start date, end date, extension papers, provider returns, and agency records. Data gathered outside the approved window can raise hard questions.
Sealing and Nondisclosure
A South Dakota order must direct that it be sealed until the court orders otherwise. It must also direct the person who owns or leases the line, or the person ordered to help, not to disclose the existence of the pen register, trap-and-trace device, or investigation to the listed subscriber or to anyone else unless the judge allows it.
This is why a person may not learn about the order while it is active. A provider may be under a direct court command to stay silent.
A company that receives such an order should route it to counsel or a trained legal-response person. It should not be sent through casual office messages or discussed with the account holder.
Assistance With a Pen Register
When a court order directs help, a provider of wire or electronic communication service, landlord, custodian, or other person must provide the information, facilities, and technical assistance needed to install the pen register.
The statute says the help must be supplied immediately. The installation should be done unobtrusively and with minimal interference with the service provided to the person whose line or device is involved.
The provider is not acting as a private detective. It is obeying a court order. The order controls the scope, not curiosity or convenience.
Assistance With a Trap-and-Trace Device
For a trap-and-trace device, a provider, landlord, custodian, or other ordered person must install the device immediately on the proper line or electronic device. The ordered person must also provide information, facilities, and technical help for installation and operation.
Unless the court orders a different method, the results are furnished to the law enforcement officer named in the court order at reasonable intervals during regular business hours for the duration of the order.
This setup gives the court order a rhythm. The provider gathers or supports the approved incoming-origin data. The named officer receives the results inside the order’s time period.
Payment for Assistance
A provider, landlord, custodian, or other person who furnishes facilities or technical help under these sections must be reasonably paid for reasonable expenses.
That payment rule recognizes that compliance can take staff time, system work, records work, and technical setup. It also helps keep the response tied to a formal legal process, not an unpaid favor.
A business should document what it did, when it did it, and what costs were tied to compliance. Clean records can prevent later confusion.
Immunity for Helpers
South Dakota law says no cause of action may lie against a provider of wire or electronic communication service, its officers, employees, agents, or other specified people for providing information, facilities, or assistance according to the terms of the court order.
That protection is for compliant help. It does not invite a provider to hand over extra accounts, extra dates, or message contents outside the order.
The best response is narrow. Read the order. Follow the order. Keep a clear record. Do not add more just because it is easy to export a larger file.
Good-Faith Reliance
South Dakota also gives a good-faith defense. Good-faith reliance on a court order, legislative authorization, or statutory authorization is a complete defense against civil or criminal action under the pen-register and trap-and-trace sections or any other law.
This helps people who follow lawful papers in good faith. It does not protect careless overreach as well as careful compliance does.
For providers and other helpers, the safe habit is simple: limit access to the order, get legal review, match the response to the order, and document each step.
How This Differs From Wiretapping
Wiretapping or interception reaches the contents of a communication. That means the identity of parties, existence, substance, purpose, or meaning of a wire, electronic, or oral communication under South Dakota’s definitions. State law treats interception and eavesdropping as separate matters with different rules.
A pen register or trap-and-trace device is narrower. It is aimed at numbers and outside signal data. It should not record the conversation or read the message body.
The split is like reading a package label versus opening the package. Trap-and-trace law studies the label. Wiretap law steps into the package itself. The law treats those steps differently because one reaches much deeper into privacy.
One-Party Consent Is a Different Issue
South Dakota has rules that allow a party to a communication, or a person with consent from one party, to record in some settings. That recording rule is often called one-party consent.
Do not confuse that with pen registers and trap-and-trace devices. Consent to record a conversation you are part of is one question. Installing or using a device that traces someone else’s incoming or outgoing communication traffic is another.
A person can be allowed to record their own conversation and still be barred from secretly tracing someone else’s line, account, device, or communication system.
Tracking Devices Are Separate
South Dakota has a separate tracking-device warrant rule in SDCL 23A-35-4.3. A tracking device means an electronic or mechanical device that permits tracking the movement of a person or object. The definition includes GPS, cellular devices, electronic video surveillance, and other covert tracking or surveillance devices.
A tracking-device warrant requires probable cause. The warrant must identify the person or property to be tracked, name the magistrate to whom it must be returned, and set a reasonable use period. That period may not exceed 60 days, though extensions may be granted for good cause.
This is not the same as trap-and-trace law. A trap-and-trace device tracks incoming communication origin. A tracking device follows movement. A phone can create both contact trails and movement trails, but the legal roads are different.
Notice After Tracking
South Dakota’s tracking-device warrant rule has a notice feature. Within 10 days after tracking-device use ends, the officer must serve a copy of the warrant on the person who was tracked or whose property was tracked, unless notice is delayed under the statute.
The judge may delay notice to prevent danger, flight, evidence destruction or tampering, witness intimidation, or serious harm to an investigation or trial timing.
That notice system is not the same as the sealing and nondisclosure rule for pen registers and trap-and-trace devices. The state separates contact tracing from movement tracking.
Private People Should Not Try This
A private person should not install hidden software, hardware, router settings, call-forwarding rules, spyware, account filters, or tracing setups to follow someone else’s communications. Suspicion is not enough. A breakup is not enough. A business dispute is not enough. Paying the bill may not be enough.
Do not log into another person’s account to learn who contacted them. Do not hire someone to trace calls or messages outside lawful process. Do not place monitoring equipment on a phone line, router, laptop, office system, shared account, or phone for personal reasons.
South Dakota’s pen-register statute, federal law, computer-crime rules, stalking and harassment laws, privacy claims, family-court orders, workplace rules, and civil claims can all come into play. A secret trace can turn into a legal pit.
Employers and Business Systems
Employers often keep phone logs, email routing logs, access records, network logs, security alerts, payment records, and fraud records. Some logging may be normal when tied to service upkeep, cybersecurity, billing, fraud control, or abuse response.
But secret tracking of private communications can create risk. Company ownership of a phone, laptop, router, email account, or work system does not answer every question. Written policy, notice, consent, business need, data type, and access limits all matter.
A South Dakota employer should get legal review before adding systems that trace worker communication patterns beyond ordinary business logging. The safer route is written policy, narrow collection, limited access, and clean records.
Website Tracking and New Data Questions
Pen-register and trap-and-trace wording began in the phone world, but newer disputes can involve websites, mobile apps, analytics scripts, chat boxes, ad pixels, device IDs, IP logs, and account tracking. These systems can send user activity to outside vendors without much visible sign on the screen.
Not every web-tracking case is a pen-register case. Some turn on wiretap law, consumer law, contract terms, health privacy, consent banners, account notices, or how data moves to a vendor.
South Dakota businesses should review tracking systems before launch. A small script can act like a keyhole if it passes too much user activity to the wrong party.
What South Dakota Residents Should Know
For South Dakota residents, the practical point is that law enforcement may seek a circuit-court order for non-message communication tracing during an ongoing criminal investigation. The target or subscriber may not receive notice while the order is active because sealing and nondisclosure rules apply.
The data may later appear in warrant papers, charging records, discovery, or motion practice. It may show outgoing numbers, incoming origins, timing, and contact patterns. Even without spoken words, that data can carry force.
If you learn that one of these orders was used in a case involving you, a South Dakota criminal defense lawyer can review the application, relevance certification, order, dates, extension papers, provider returns, and whether the data stayed inside the court-approved boundary.
What Providers and Businesses Should Do With an Order
A provider, landlord, custodian, platform, or business that receives a South Dakota order should treat it as legal process. Preserve the document. Limit internal access. Send it to counsel or a trained legal-response person.
Read the order closely. Check the court, date, covered telephone line or electronic communication device, physical location if listed, data type, time period, named officer, assistance language, sealing language, and nondisclosure command. Provide what the order requires, not extra data from extra accounts or extra dates.
Keep a clean record of the response. Note when the paper arrived, who reviewed it, what help was given, what data was furnished, and when. A careful response is like tying down a gate before prairie wind arrives. It keeps the matter from swinging loose later.
Common Misunderstandings
One common misunderstanding is that trap and trace means listening to calls. It does not. It points to incoming identifying data, not the words spoken.
Another misunderstanding is that a pen-register order requires probable cause in South Dakota. The state pen-register and trap-and-trace sections use a relevance certification tied to an ongoing criminal investigation. Tracking-device warrants, by contrast, use probable cause.
A third misunderstanding is that a provider may freely warn the subscriber. The order must be sealed, and the person ordered to help may not disclose the device or investigation unless the judge allows it.
A final misunderstanding is that contact data has little privacy value. It can show habits, repeated contacts, timing, and relationships. A call trail can be a shadow map of a person’s life.
Bottom Line on South Dakota Trap and Trace Law
South Dakota trap and trace law sits mainly in SDCL 23A-35A-22 through 23A-35A-34. A pen register records or decodes outgoing number data on the communication system where it is attached. A trap-and-trace device captures incoming impulses that identify the originating number of the instrument or device that sent the communication.
South Dakota generally bars installation or use of a pen register or trap-and-trace device without first getting a court order. A violation is a Class 1 misdemeanor. An investigative or law enforcement officer may apply in writing under oath to a circuit court judge. The application must identify the officer and agency and certify that the information likely to be obtained is relevant to an ongoing criminal investigation.
If the court finds that certification was made, it enters an ex parte order. The order must name known line or device listing information, known investigation subjects, numbers and physical locations if known, trap-and-trace geographic limits, the related offense, and any required assistance. The order may last no more than 60 days, with 60-day extensions through the same process. The order is sealed, and disclosure to the subscriber or others is barred unless the judge allows it.
Providers, landlords, custodians, and other ordered helpers must give technical assistance with minimal service interference, must be reasonably paid, and receive protection when they comply with the order. Good-faith reliance on a court order or statutory authorization is a complete defense. Tracking devices are separate and require a search warrant with probable cause under SDCL 23A-35-4.3. The law does not open the letter, but it can study the envelope. In South Dakota, that envelope still has rules wrapped tightly around it.