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For 3CX, FreePBX, Asterisk, Yeastar and any SIP phone system

The prepaid SIP trunk provider that calls abroad on day one.

Most SIP trunk providers rent you channels by the month and keep international locked behind a review. LinkedSIP is a prepaid SIP trunk service: no channel fees, no ID, and calls to 200+ countries open from your first $20 top-up. If a password ever leaks, your balance is the most it can cost.

Open a trunkCompare providers
SIPLinkedSIP trunkPrepaid, outbound, international
a month
$0
per channel
$0
to start, in crypto
$20
of routes billed per second
71%
calls abroad open
Day 1
a verified email is enough
No ID

G.711, no contract, answered calls only. Not included: trial credit and emergency calls. Draft prices during the preview.

+

International calls on a SIP trunk

Most trunks keep calls abroad locked. Ours open with your first top-up.

International calling is where toll fraud makes money, so many providers switch it off for new accounts and open it after a ticket, an application or an ID check. We cap the risk with prepaid credit instead, so there is nothing to unlock.

  • LinkedSIPOpenOpen from your first top-up
  • TwilioPartly openPer-country dialing permissions; trial calls to low-risk countries only
  • TelnyxLocked at firstNeeds Level 2 verification, approved in up to 48 hours
  • SIP.USLocked at firstOff until support enables it; default cap of $0.30 a minute
  • VoIP.msLocked at firstOff by default
  • CallcentricPartly openCalls over $0.40 a minute blocked until you verify or pay by wire
  • DIDWWLocked at firstOutbound access by application, answered within 48 business hours
  • FlowrouteNot statedNot stated
  • SkyetelLocked at firstNew accounts US and Canada only; international by ticket
Read from each provider's own help and pricing pages on 26 Oct 2026.
$0

What the trunk costs you

Pay for the minutes you talk, not the lines you rent.

Most business trunks charge for every channel, every month, whether a call is on it or not. Office calls come in bursts. Put in your busiest hour and see how many lines you would be renting.

You need about 10 calls at once. With that many, 0.5% of busy-hour calls would find every line busy.

A per-channel trunk$100 to $250a month for 10 channels, before the first minute
LinkedSIP$0for channels. Ask, and your SIP login's limit is raised to 10 calls at once

Erlang B at 1% blocking, the standard traffic formula. Channel prices are the market range in a published review of SIP trunk providers. Minutes cost the same per-minute rate on both, so they are left out.

How your minutes are rounded

The rate is half the price. The other half is the billing increment: a 61-second call billed per minute costs two minutes. We publish the increment beside every rate, and most routes bill by the second.

  • 71% per second1,861 ranges
  • 28% 6-second steps725 ranges
  • 2% per minute44 ranges
2,630 priced number ranges on the draft price list, by how each call is rounded.
  • Per second61 s
  • 6-second steps66 s
  • Per minute120 s
Coral is the 61 seconds you talked. The pale part is rounding you pay for anyway.
5060

SIP trunk fraud protection

Three locks between a stolen SIP login and your money.

Bots scan the internet for phone systems on port 5060, guess a password and call expensive number ranges that pay the attacker a share. On a trunk billed afterwards there is no top to the bill. These three locks run on every LinkedSIP account.

  1. HOLD

    Credit is held before each call

    Before a call connects, credit for its first stretch is set aside, and the call only runs as long as credit covers it. What is not used comes back when it ends. There is no credit line, so the balance cannot go below zero.

  2. +881

    Costly ranges start closed

    Premium, special and satellite ranges are where stolen logins earn money. They are blocked on every account until you ask for them, so the usual cash-out route is shut from the start.

  3. MAX

    Every login has its own ceiling

    Give each office, team or device its own SIP login with its own limit on calls at once. One leaked password can never use every line on the account.

Lock your own phone system too

Our locks cap the damage. These stop the break-in, on any provider:

  • Long random SIP passwords, never the extension number and never reused.
  • Allow SIP only from the addresses that need it, or use your PBX firewall and fail2ban-style blocking.
  • Close international dialling on extensions that never call abroad.
  • Change default admin logins on the PBX, phones and router the day you install them.
  • Read the call log weekly. Calls at 3 am to a country you never call are the first sign.
VS

SIP trunk providers compared

Nine SIP trunk providers, read from their own pages.

We read the pricing, sign-up and help pages of eight well-known providers on 26 Oct 2026. Where a page did not say, we say so. Our own weak spot, payment, is in the table too.

ProviderHow it is pricedBilling incrementInternational at sign-upSign-up checksSpend controlsHow you pay
LinkedSIPPrepaidPer minute. $0 a month, $0 per channel, $0 setupPer country. 71% of ranges per second, the rest 6 or 60 secondsOpen from your first top-upVerified email. No IDPrepaid balance is a hard ceiling. Credit held per call, premium ranges blocked, call limit per loginCrypto only, from $20. No card or invoice
TwilioElastic SIP TrunkingPer minute. No contracts, no channel limitsRounded up to the next full minutePer-country dialing permissions; trial calls to low-risk countries onlyNot stated on the pages we readGeographic permissions by country and risk levelCard or PayPal; invoices from $12k a year committed
TelnyxElastic SIPPer minute from $0.005 (US), or inbound channels from $8 to $12 a monthNot statedNeeds Level 2 verification, approved in up to 48 hoursPayment review up to 48 hours. 2 calls at once until Level 2, then 10Daily spend limit per connection, max rate, country allow listCard or PayPal (3% fee), ACH, Bitcoin from $100 for verified accounts
SIP.USBCM OnePer channel: $24.95 a month, $19.99 on yearly plans. Unlimited US48 and CanadaNot statedOff until support enables it; default cap of $0.30 a minutePayment validation up to 24 hoursMax call cost and high-fraud countries blocked by defaultCard; ACH after the first deposit
VoIP.msPer minute from $0.005. $15 minimum depositMostly 6 seconds; Mexico and some others 60Off by defaultCompliance review may ask for government ID and business registrationPer-minute rate ceiling and call-time caps for internationalNot confirmed (pages blocked automated reading)
CallcentricPay Per CallPer minute. $0 setup, $0 monthly, deposits from $5Whole minutes unless the rate says otherwiseCalls over $0.40 a minute blocked until you verify or pay by wireCredit check or fraud score at sign-upMax-rate and allowed-area settingsCard, PayPal for verified accounts, wire with a fee
DIDWWPer minute, plus flat or metered channel capacity. $30 minimum balancePer your rate sheetOutbound access by application, answered within 48 business hoursApplication; identity checks possibleChannel cap per trunk, 24-hour spend limit, prefix allow and block listsCard, PayPal, wire
FlowroutePer minute from $0.00833 (US). PrepaidMostly 6 seconds; Mexico mobile 60Not statedVerification may ask for more informationToll fraud protection mentioned, no detailsCard or wire
SkyetelFlat domestic, per-route international, prices not published. $25 monthly minimum after 90 daysNot statedNew accounts US and Canada only; international by ticketPhoto ID check for every account, companies onlyPrepaid, calls stop at $0. Trust tiers and a $1,000 monthly fraud limitCard

Checked against each provider's own pricing, help and terms pages on 26 Oct 2026. Prices and terms change, so check the provider's page before you buy. LinkedSIP has no business ties to any provider listed.

Choose LinkedSIP if you call abroad, want a hard ceiling on spend and would rather not send ID or rent channels.
Choose another provider if you need card or invoice billing, emergency calling, trial credit or unlimited US and Canada calling per channel.
PBX

An outbound SIP trunk next to the one you have

Keep your carrier. Send calls abroad through us.

You do not have to move your numbers. Add LinkedSIP to your phone system as a second trunk, and one outbound rule sends every call that starts with + or 00 our way. Local calls stay where they are.

Which phone system do you run?

3CX
FreePBX
Asterisk
Yeastar
SIP app

In the US and Canada people dial 011 to call abroad: add that pattern too. Numbers must reach us in international format, + or 00 and then the country code.

+00LinkedSIPCalls abroad, prepaid
012Your current trunkLocal calls and emergency numbers, as today

Pick your phone system above to see the rule in its own words.

FAQ

SIP trunk provider questions

What does a SIP trunk provider do?
It connects your phone system to the public phone network over the internet. You add the provider to your PBX as a SIP trunk with a server, a username and a password, and it carries your calls to landlines and mobiles, billing each one by the minute. For channels, SIP vs PRI and security, read what a SIP trunk is.
Who are the top SIP trunk providers?
Lists usually name Twilio, Telnyx, Bandwidth, Vonage, SIP.US, VoIP.ms and DIDWW. The best one is the one that fits how you call: compare price model, rates and increments for your countries, when international opens, how you pay and what caps a hacked system. The table above does that for nine providers.
Is there a free SIP service?
Calls between SIP accounts can be free, but calls to real landlines and mobiles always cost someone, because a carrier has to complete them. Free SIP trunk offers are usually a trial. LinkedSIP has no trial credit: the account is free and the smallest top-up is $20.
How do I set up a SIP trunk?
Open an account, add credit, and copy your SIP login. In your PBX, add a trunk with the server, username and password, put G.711 first in the codec list, then add an outbound rule that sends calls to the trunk. Turn off SIP ALG on your router if registration or audio fails.
How many SIP channels do I need?
Count the most calls you run at the same moment in your busiest hour, then add a little headroom, or use the meter above. On LinkedSIP channels cost nothing: the number is only a safety limit on your login, and we raise it when you ask. The rest of the price list is on the SIP trunk pricing page.
What is the difference between SIP and VoIP?
VoIP is any voice call carried over the internet. SIP is the protocol most VoIP systems use to start and end those calls, and a SIP trunk is the connection that links your phone system to the phone network with it.
Can I use LinkedSIP for inbound calls?
Yes, with a local number in another country for $0.99 a month, paid from the same balance. The trunk itself is built for outbound calls.
Can I call emergency services?
No. LinkedSIP cannot reach emergency numbers. Keep a landline, a mobile or your current trunk for them, which the second-trunk rule above does for you.

Your phone system is ready. The trunk takes ten minutes.

An email, a $20 crypto top-up and three settings. No ID, no channel fees, and no bill bigger than your balance.

Open a trunkHow LinkedSIP works