Phone Line Type

Line Type Taxonomy

Each line type has distinct characteristics that affect how you should treat the number:

Line type	Description	SMS capable?	Fraud risk
Wireless	Mobile devices on cellular networks	Yes — native	Low — requires identity verification
Landline	Traditional wired telephone service	No — text-to-speech only	Very low — tied to physical address
VoIP	Internet-based phone services	Varies by provider	High — easily obtained anonymously
Prepaid	Wireless with no long-term contract	Yes	Elevated — no identity binding
Toll-free	800/888/877/866 numbers	If SMS-enabled by owner	Low — business registration required

Line Type as a Primary Fraud Signal

VoIP numbers are the single most reliable phone-level fraud indicator. Unlike wireless numbers, which require identity documentation and credit checks with a carrier, VoIP numbers can be provisioned instantly from dozens of providers with no identity verification. Fraud prevention platforms consistently report that VoIP numbers are 3–5× more likely to be associated with fraudulent account registrations, chargebacks, and synthetic identity fraud than wireless numbers from postpaid carriers.

Prepaid wireless adds a secondary risk tier. Prepaid numbers require less identity verification than postpaid, can be purchased anonymously, and are commonly associated with temporary use fraud patterns such as account takeover via SMS OTP interception. They are not inherently fraudulent — many legitimate users prefer prepaid — but prepaid at the point of account creation, combined with other risk signals, warrants additional verification.

A fraud scoring model that treats all wireless equally misses the postpaid/prepaid distinction. Line type lookup provides the first-level signal; combine it with LRN activation date (how recently the number was ported) and spam score for a complete risk picture.

TCPA Compliance: Why Wireless Verification Matters

The Telephone Consumer Protection Act (TCPA) requires prior express written consent before sending marketing messages to wireless numbers using an automatic telephone dialing system (ATDS). The same requirement does not apply to landlines under the ATDS rules. This means the TCPA exposure for a given outreach campaign depends directly on the line type of the numbers in the list.

Line type lookup at the point of list acquisition — before any dialing or messaging begins — lets compliance teams segment the list and apply the correct consent standard to each number. Sending ATDS messages to wireless numbers without documented consent exposes senders to statutory damages of $500–$1,500 per call or message. At any scale, unchecked wireless numbers in a dialing list represent material legal risk.

Contact centers should also note that landlines cannot receive SMS reliably. Sending SMS campaigns to landlines wastes budget and inflates undelivered message counts. Filtering landlines from SMS campaigns before sending is standard practice for any team monitoring cost-per-delivered-message.

How Line Type Affects CNAM Data Quality

CNAM (Caller ID Name) data quality varies significantly by line type, and understanding this relationship prevents misinterpreting CNAM results:

Line type	CNAM availability	Accuracy
Landline	High — most have registered CNAM	Generally accurate; updated infrequently
Wireless	Low — carriers rarely provision CNAM	Often blank; third-party name data required
VoIP	Variable — set by provider	Often generic or spoofed; low trust
Prepaid	Very low	Rarely available
Toll-free	High — owner-controlled	Accurate for the registering business

A blank CNAM result on a wireless number is expected and not an error. A blank CNAM on a landline warrants a second lookup or a flag for manual review. Running line type first tells you which interpretation is correct.

Line Type in the VeriRoute Intel API Response

VRI returns carrier_type as part of every LRN lookup. No additional parameter is needed — it is included in the enhanced_lrn object automatically.

curl -X POST https://api-service.verirouteintel.io/api/v1/lrn \
  -H "Authorization: Bearer YOUR_API_KEY" \
  -H "Content-Type: application/json" \
  -d '{"phone_number": "14155551234", "include_enhanced_lrn": true}'

# Response
{
  "phone_number": "14155551234",
  "lrn": "14155550000",
  "lrn_activated_at": "2021-04-22T00:00:00Z",
  "enhanced_lrn": {
    "carrier": "Google Voice",
    "carrier_type": "VOIP",
    "ocn": "8543",
    "state": "CA"
  }
}

The carrier_type field returns one of: WIRELESS, LANDLINE, VOIP, TOLLFREE, or PREPAID. Use this value to gate routing decisions, apply TCPA consent logic, and adjust fraud scoring — without any post-processing needed on the carrier name string.

Applying Line Type in Fraud Scoring

import httpx

def score_phone(phone: str, api_key: str) -> dict:
    resp = httpx.post(
        "https://api-service.verirouteintel.io/api/v1/lrn",
        headers={"Authorization": f"Bearer {api_key}"},
        json={"phone_number": phone, "include_enhanced_lrn": True},
    ).json()

    carrier_type = resp["enhanced_lrn"]["carrier_type"]
    days_since_port = (
        (datetime.utcnow() - datetime.fromisoformat(
            resp["lrn_activated_at"].replace("Z", "")
        )).days
        if resp.get("lrn_activated_at") else 9999
    )

    risk = 0
    if carrier_type == "VOIP":
        risk += 30  # High-risk line type
    elif carrier_type == "PREPAID":
        risk += 15  # Elevated risk
    if days_since_port < 30:
        risk += 25  # Recent port is a strong fraud signal

    return {"carrier_type": carrier_type, "risk_score": risk}

Related Terms

• LRN
• VoIP
• Landline