// Glossary
Line Type
Whether a phone number is mobile, landline, or VoIP, which affects how you can reach it by SMS and which consent rules apply.
Definition
Line type classifies a phone number as mobile (wireless), landline (fixed), or VoIP (internet-based). It matters for outreach because SMS only works on mobile and some VoIP numbers, and because regulations like the TCPA impose stricter consent rules on calls and texts to wireless numbers. Identifying line type before dialing or texting helps you route contacts correctly and stay compliant.
Why line type matters before you dial
Line type classifies a phone number as mobile, landline, VoIP, or toll-free. It matters because the channel you can legally and effectively use depends on it: SMS needs a mobile, and TCPA rules treat autodialed calls and texts to mobiles more strictly than landlines. Knowing the line type before you contact someone lets you route the right channel and screen against Do-Not-Call lists. Trackyr resolves line type via PhoneValidator on verified numbers.
Common questions
How is line type detected?+
A phone-validation service performs a carrier/HLR-style lookup that returns the number's current line type (mobile, landline, VoIP, toll-free) and whether it's active.
Why does line type affect compliance?+
US TCPA rules treat autodialed calls and texts to mobile numbers more strictly than landlines, so knowing the line type helps you contact people through a compliant channel.
Put line type to work.
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