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SIPNEX
Toll-Free Numbers

Toll-free numbers on a toll-free SIP trunk. Direct from the RespOrg.

800, 888, 877, 866, 855, 844, 833 — all prefixes, vanity search, 24-hour provisioning. SIPNEX is a registered RespOrg. We manage your toll-free numbers directly in the national database and deliver them to your phone system over SIP.

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The basics

What is toll-free number service?

Toll-free number service gives a business a phone number that callers dial free of charge. The prefix is 800, 888, 877, 866, 855, 844, or 833. It is a free service for the caller, not for the business — you pay the per-minute inbound cost. A RespOrg reserves the number in the national SMS/800 database and routes inbound calls to your phone system.

SIPNEX is that RespOrg — not a reseller working through one. Reservation, routing, CNAM registration, and STIR/SHAKEN signing happen in-house. That is how a toll-free number goes live within 24 hours instead of a week.

Delivery is a toll-free SIP trunk. The number is routed to your phone system over SIP trunking, and inbound calls and outbound caller ID ride the same trunk.

SIP delivery

What is a toll-free SIP trunk?

A toll-free SIP trunk carries calls to your 8XX number from the carrier to your phone system over the Session Initiation Protocol (SIP). The number itself is not a phone line. It is a routing record in the SMS/800 database that tells the network which carrier receives the call. On SIPNEX, that carrier hands the call to the trunk: a logical connection that carries your simultaneous calls over your internet link.

Capacity is counted in concurrent calls, also called channels. One channel is one call in progress. A legacy PRI sold channels in blocks of 23 per T1 circuit. A SIP trunk adds them one at a time, limited by your bandwidth, your PBX, and any ceiling the carrier sets — which is why question 4 below matters. That is what makes SIP the cost-effective way to carry call volumes that swing between quiet mornings and campaign peaks.

The same mechanics serve a small business with one published line and enterprise-grade contact centers running inbound queues, an IVR, and dozens of agents. The trunk can point at an on-premises PBX, a hosted PBX, or a unified communications platform — whatever answers the call.

SIP keeps signaling and media separate, so each can be encrypted on its own. TLS on port 5061 protects the signaling; SRTP protects the audio. Together, TLS/SRTP cover the leg between your PBX and the carrier. Confirm both before turn-up, along with the concurrent-call ceiling.

Registered RespOrg

SIPNEX manages toll-free numbers directly in the SMS/800 database. No intermediary delays. No third-party RespOrg coordination. Direct carrier provisioning.

All 7 Prefixes

800, 888, 877, 866, 855, 844, and 833. We search all prefixes to find the best available number. Standard and vanity numbers available.

24-Hour Provisioning

Number reserved, routing configured, CNAM registered, and STIR/SHAKEN attestation active within one business day. Carrier-direct speed.

Vanity Number Search

Search available toll-free inventory for letter combinations that spell your business name or service. If the combination is available, standard pricing applies — no premium.

A-Level Attestation

Every toll-free number receives A-level STIR/SHAKEN attestation on outbound calls. Signed with our own SP-KI certificate. Same trust signal as local DIDs.

Inbound + Outbound

Every toll-free DID supports both inbound routing and outbound CID on the same SIP trunk. Use it as your published business line and as outbound caller ID.

SIPNEX vs typical toll-free provider.

SIPNEXTYPICAL PROVIDER
RespOrg statusDirect RespOrgUses third-party RespOrg
Provisioning speed24 hours3–7 business days
STIR/SHAKENA-level (own cert)B-level or none
CNAM registrationIncludedExtra charge
Setup feesNone$10–$50
Porting feesNone$5–$25 per number
Vanity searchDirect SMS/800 searchLimited third-party search
All 7 prefixesYesOften limited selection
Capacity

Sizing a toll-free SIP trunk for your call volumes.

Size the trunk for peak simultaneous calls, not the daily average. Each G.711 call consumes about 85 kbps per direction — 64 kbps of audio plus IP, UDP, and RTP headers. Voice needs that bandwidth upstream as well as downstream, so check both sides of the link.

CONCURRENT CALLSG.711 (~85 KBPS/CALL)G.729 (~32 KBPS/CALL)
5 calls~0.4 Mbps each way~0.2 Mbps each way
25 calls~2.1 Mbps each way~0.8 Mbps each way
100 calls~8.5 Mbps each way~3.2 Mbps each way
200 calls~17 Mbps each way~6.4 Mbps each way
500 calls~43 Mbps each way~16 Mbps each way

G.711 is the high-quality choice: uncompressed audio at 64 kbps with a MOS baseline of 4.4. G.729 compresses the voice to 8 kbps and gives up some clarity for bandwidth. On a modern business connection the saving rarely matters, so most operations run G.711.

Call quality on the trunk depends on the network path more than on the codec. Hold jitter below 30 ms and packet loss below 1 percent; past those marks callers hear choppy audio. Put voice on a wired connection with QoS and measure before launch day. The packet-loss diagnostics are in how to fix packet loss on VoIP calls, and the channel math — peak concurrency plus headroom — is in how many SIP trunks you need.

Vanity numbers

What is a vanity toll-free number?

A vanity toll-free number spells a word or phrase on the phone keypad — 1-800-FLOWERS translates to 1-800-356-9377. Under the hood it is a standard toll-free number: same routing, same CNAM, same STIR/SHAKEN attestation. The letters are a memorability device for your marketing, nothing more.

How it works: vanity combinations are first-come, first-served in the SMS/800 database. As a registered RespOrg, SIPNEX searches that database directly across all seven prefixes. If your combination is open, we reserve it at standard toll-free pricing — no premium, live within 24 hours.

If it is taken, a number broker may hold it for resale at a one-time price that varies by desirability ($200 to $50,000+). We assist with broker acquisitions — and we will say so when a standard number serves you just as well. On outbound caller ID, recipients see digits, not letters. A vanity number earns its keep on inbound calls and offline advertising.

Before you order

Six questions for any toll-free provider.

Put these to a provider before you order a number. The answers tell you who you are dealing with. Is it the RespOrg itself, or a reseller that files tickets with one?

  1. Who is the RespOrg of record? The RespOrg controls the routing record and processes the port. A reseller files a ticket with one; a RespOrg changes the record itself.
  2. Which prefixes can it search? All seven — 800, 888, 877, 866, 855, 844, and 833 — or a subset? Inventory differs by prefix, and 833 has the most open numbers.
  3. Who signs STIR/SHAKEN on outbound calls from the number? A toll-free number gets an A-level signature only when the provider signs with its own SP certificate. That puts it on par with a local DID. A B-level (partial) signature is a lower-trust signal in the analytics engines’ scoring.
  4. What is the concurrent-call ceiling? Find out what the next caller hears when every channel is busy. Ask, too, whether each channel carries a monthly fee.
  5. Does the trunk support TLS and SRTP? Signaling and media are encrypted separately; you want both.
  6. What does leaving cost? Toll-free numbers move by RespOrg transfer, typically 5 to 15 business days. Ask about port-out fees in writing before you sign.

Frequently asked questions.

How quickly can I get a toll-free number?
SIPNEX provisions toll-free numbers within 24 hours. We are a registered RespOrg — we reserve numbers directly in the SMS/800 database without intermediaries. Your number is live for inbound and outbound use within one business day, including CNAM registration and STIR/SHAKEN attestation setup.
What toll-free prefixes are available?
All seven toll-free prefixes: 800, 888, 877, 866, 855, 844, and 833. Availability varies by prefix — 800 numbers have the most limited inventory (most desirable combinations are taken), while 833 numbers have the most availability. We search all prefixes to find the best available number for your needs.
Can I get a vanity toll-free number?
If the vanity combination you want is available in the SMS/800 database, we reserve it at standard toll-free pricing — no acquisition premium. If it is taken, it may be available through a number broker at a one-time purchase price that varies by desirability ($200 to $50,000+ for premium combinations). We can assist with both scenarios.
How much does a toll-free number cost?
Monthly DID fee: $2 to $5 per number. Per-minute inbound charges apply — you pay for incoming minutes because toll-free means free for the caller, not free for the business. No setup fees. No porting fees. See our pricing page for the current rate card.
Can I port my existing toll-free number to SIPNEX?
Yes. Toll-free porting uses the RespOrg transfer process. You authorize SIPNEX as the new RespOrg, we submit the transfer request, and routing switches to our network. Timeline: 5 to 15 business days depending on the current RespOrg’s processing speed. Your number remains active during the transfer.
What is a RespOrg?
RespOrg (Responsible Organization) is the entity authorized to manage toll-free number routing in the national SMS/800 database. SIPNEX is a registered RespOrg — we manage toll-free numbers directly without intermediaries. This means faster provisioning, direct routing control, and no middleman delays.
Should I use toll-free or local numbers for outbound calling?
For outbound campaigns, local numbers outperform toll-free in answer rate by 15 to 30 percent. Consumers associate toll-free calls with telemarketing. For inbound (customer service, sales inquiries, published business lines), toll-free is preferred — it signals an established business and eliminates cost barriers for the caller. Most operations use both: toll-free for inbound, local DIDs for outbound.
Do toll-free numbers get STIR/SHAKEN attestation?
Yes. SIPNEX-provisioned toll-free numbers receive A-level STIR/SHAKEN attestation on outbound calls, identical to local DIDs. We sign with our own SP-KI certificate. Toll-free numbers are also usable as outbound CID, though local numbers typically produce better answer rates for outbound campaigns.
Does a vanity toll-free number cost more per month?
No. On SIPNEX the monthly cost is identical to a standard toll-free number — the $2 to $5 DID fee plus per-minute inbound usage, with no recurring premium for the letter combination. The only extra cost is the one-time broker price when the combination you want is already taken; if it is open in the SMS/800 database, we reserve it at standard pricing.
Is a toll-free number the same as a phone line?
No. A toll-free number is a routing record in the national SMS/800 database, not a line. The record names the carrier that receives the call; on SIPNEX, that carrier delivers it over a SIP trunk into your PBX or contact center platform. Because the number and the destination are separate, you can change where calls land without changing the number, and the number stays in service while it moves to a new RespOrg.
How many simultaneous calls can one toll-free number handle?
The number itself sets no limit; the trunk and the phone system behind it do. Each simultaneous call takes one channel on the trunk and about 85 kbps of bandwidth in each direction on G.711. Size for the busiest hour you expect, add headroom, and get the provider’s concurrent-call ceiling in writing.
Can toll-free calls on a SIP trunk be encrypted with TLS and SRTP?
Yes. SIP carries signaling and media separately, so each is encrypted on its own: TLS on port 5061 for the signaling and SRTP for the audio. Encryption covers the leg between your PBX and the carrier — the stretch where SIP credentials and call content cross the public internet. Turn both on at the PBX and verify they are active before go-live.

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