Glossary
Phone Line Type: Mobile, Landline or VoIP
What is phone line type?
Short answerLine type is the classification of a phone number by the kind of service behind it -- mobile, landline, VoIP, or toll-free. It is determined by querying carrier records, not by reading the number. In North America the same area code and prefix can be issued to either a mobile or a landline, and number portability means a line may have moved between them. Line type is separate from whether the line is still connected: a disconnected mobile is still classified as a mobile, so the two have to be checked independently.
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On this page
Line type is the most useful single field you can add to a purchased list, because it determines two separate things at once: whether a message can physically arrive, and how much legal risk the number carries.
The line types you will see
| Line type | Receives SMS | Notes for outbound |
|---|---|---|
| Mobile | Yes | Reachable by call and text, but carries the strictest TCPA consent rules. Verify consent and litigator status first. |
| Landline | No | Calls connect; texts fail silently. Remove before any SMS campaign. |
| VoIP | Sometimes | Internet-based. Cheap to create and discard, so concentrated in poor-quality lists. |
| Toll-free | Rarely | An 800/888/877 business line billed to the receiver. A company switchboard, not a consumer lead. |
| Disconnected | No | No longer in service. Wastes agent time and depresses connect rates. |
Why the number itself tells you nothing
Two mechanisms defeat any attempt to infer line type from the digits:
Prefix blocks are mixed. The North American Numbering Plan never reserved separate ranges for mobile and fixed lines the way some countries did. A given area code plus prefix can contain both.
Numbers move. Local number portability lets a subscriber carry a number between carriers and between service types. Any static lookup table built on prefix assignment is out of date the moment porting occurs -- and porting is routine. How to find a number's carrier covers the routing mechanism that makes a current answer possible.
This is why free "area code lookup" tools cannot answer the question, and why carrier-level validation costs money: it queries live records rather than a cached table.
Quick check: what line type tells you
Pick an answer to see whether it is right, and why.
The compliance angle
The TCPA's strictest requirements attach to mobile numbers: a marketing call or text to a mobile made with an autodialer or a prerecorded voice needs prior express written consent. A prerecorded marketing call to a residential landline needs the same consent, so line type tells you which rule applies to autodialed calls and texts, not to prerecorded ones.
It cuts both ways. Identifying mobiles tells you where your legal exposure is concentrated; identifying landlines and disconnected lines tells you where your spend is being wasted. A full number scrub handles both alongside the litigator check and a Do Not Call Registry scrub, which runs under your own SAN (NumberBroom includes the federal Do Not Call Registry check free on a signed-in scrub of up to 1,000 numbers, but not state lists), and if the only thing you need is landlines removed from a list, that is the narrower job.
See it on a real number
The free phone number lookup returns line type, carrier and TCPA litigator status for any US number -- 5 a day, no card required.
Frequently asked questions
Can you tell line type from the area code?
No. In the North American Numbering Plan, prefixes are not segregated by line type -- the same 202 prefix block contains both mobiles and landlines. Local number portability compounds it: a number issued as a landline twenty years ago may be a mobile today. Only a carrier-level lookup reflects current reality.
Why does line type matter for SMS?
Landlines cannot receive SMS. A marketing text sent to one is typically billed to you and never delivered, and you usually get no bounce -- so the spend disappears silently. Filtering to mobiles before a send is the single cheapest improvement to SMS economics.
Is VoIP bad?
Not inherently -- plenty of legitimate businesses and individuals use VoIP. But VoIP numbers are cheap to create and discard, so they are over-represented in low-quality, recycled and fraudulent lead lists. Treat a high VoIP proportion as a signal about the list, not a verdict on the individual.
How do I check line type in bulk?
Upload a CSV, TSV, Excel or PDF list to a bulk validator. NumberBroom removes litigator matches and appends line type, carrier, activity score and scrub status to every row it keeps, at $0.20 per number ($5 minimum per job, lower rates past 2,000 rows). For a single number, the free carrier lookup returns line type, carrier and litigator status.