Neutral Tandem is a wholesale carrier name that still shows up in phone numbering records.
Neutral Tandem started in Chicago as a tandem carrier: a company that connects calls between other phone companies instead of selling phone service to people. The company took a different name in 2013, but Neutral Tandem is still the name on some numbering records, so some lookups still show it. NANPA, which runs the North American numbering plan, lists Neutral Tandem as the holder of 16 prefixes, all in Puerto Rico.
- Name in NANPA's file
- NEUTRAL TANDEM - PR
- What it is
- Wholesale phone carrier
- Prefixes held
- 16 of 198,436 (less than 1%)
- States and territories
- Puerto Rico
- Area codes
- 2
- Pooled prefixes
- 100%, shared in blocks of 1,000 numbers
From NANPA's central office code file of October 1, 2026. A prefix is the three digits after the area code.
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A lookup shows Neutral Tandem when the number comes from a service that gets its numbers there.
Neutral Tandem rarely sells phone service to the person using the number. Internet calling apps, VoIP phone systems, call centers and business phone services get their numbers from carriers like Neutral Tandem, so a lookup shows the carrier behind the service, not the service itself.
A lookup can show Neutral Tandem for a number outside its own prefixes when the number was ported to it, or sits in a block of 1,000 numbers assigned to it, because NANPA's prefix file lists only the holder of each whole prefix.
Numbers can also move between carriers, so a lookup reads the number's carrier today, and a number with a Neutral Tandem prefix can show another company if it was ported.
All 16 prefixes Neutral Tandem holds are in Puerto Rico.
- Puerto Rico16
Neutral Tandem holds prefixes in 2 area codes, and these are its largest.
Of the prefixes NANPA dates, Neutral Tandem received the most in 2020: 11.
NANPA's file gives an assignment date for 14 of Neutral Tandem's 16 prefixes, all from 2001 on. The rest have no date in the file.
A call from a Neutral Tandem number is not spam just because of the carrier.
Numbers from wholesale carriers like Neutral Tandem are used by ordinary people on calling apps and by real businesses. They are also cheap and quick to get, so some robocallers use them too.
The carrier name alone does not make a call safe or spam: judge it by what the caller asks for, and be careful with anyone who asks for money, codes or passwords.
Check the full number with our free spam phone checker before you call back.
You can read about 5 more carrier names here.
- Onvoy Spectrum, LLCSupplies numbers to VoIP and app-based phone services, 1,770 prefixes
- Bandwidth.com CLEC, LLCSupplies numbers to VoIP and app-based phone services, 4,804 prefixes
- Fractel, LLCSupplies numbers to VoIP and app-based phone services, 2,858 prefixes
- HD Carrier, LLCNumber holder with no public description, 329 prefixes
- IP Horizon, LLCNumber holder with no public description, 616 prefixes
These are the questions people ask about Neutral Tandem.
What is Neutral Tandem?
Neutral Tandem started in Chicago as a tandem carrier: a company that connects calls between other phone companies instead of selling phone service to people. The company took a different name in 2013, but Neutral Tandem is still the name on some numbering records, so some lookups still show it.
Why does a phone lookup say Neutral Tandem?
A lookup shows Neutral Tandem when the number comes from a service that gets its numbers there. Neutral Tandem rarely sells phone service to the person using the number. Internet calling apps, VoIP phone systems, call centers and business phone services get their numbers from carriers like Neutral Tandem, so a lookup shows the carrier behind the service, not the service itself. A lookup can show Neutral Tandem for a number outside its own prefixes when the number was ported to it, or sits in a block of 1,000 numbers assigned to it, because NANPA's prefix file lists only the holder of each whole prefix. Numbers can also move between carriers, so a lookup reads the number's carrier today, and a number with a Neutral Tandem prefix can show another company if it was ported.
Is a call from a Neutral Tandem number spam?
Numbers from wholesale carriers like Neutral Tandem are used by ordinary people on calling apps and by real businesses. They are also cheap and quick to get, so some robocallers use them too. The carrier name alone does not make a call safe or spam: judge it by what the caller asks for, and be careful with anyone who asks for money, codes or passwords. Check the full number with our free spam phone checker before you call back.
How many phone prefixes does Neutral Tandem hold?
NANPA lists Neutral Tandem as the holder of 16 prefixes, less than 1% of all assigned US prefixes. A prefix is the three digits after the area code and covers up to 10,000 numbers. 100% of these are pooled, so blocks of 1,000 numbers inside them can belong to other carriers.
Which states have the most Neutral Tandem prefixes?
All 16 prefixes Neutral Tandem holds in NANPA's file are in Puerto Rico.
Can I find out who owns a Neutral Tandem number?
Neutral Tandem does not publish who uses its numbers. Our free who called me lookup shows who a US number is listed to and the city and state on the listing, when the number has a listing.
Source: NANPA, the North American Numbering Plan Administrator: its central office code assignments, as of October 1, 2026. Company histories are from public records and each company's own descriptions.