An international SIP trunk for AI calling needs a local number in each country, bought with that country's documents, and a caller ID the destination network accepts. The carrier account must allow calls to that country. Dograh, the open-source AI voice agent platform, works with any carrier's trunk, and you can self-host it or run it on Dograh Cloud.
Key Takeaways
- Carriers drop calls to countries your account has not switched on.
- UK networks block or hide calls from abroad showing UK numbers.
- Run one Dograh campaign per country so calling hours match.
This post is part of our guide to SIP trunk providers, where regions are one line in picking a provider. Below we cover the numbers you buy abroad, the caller ID rules in the UK and India, the carrier settings that stop calls and how Dograh handles each part.
Local numbers come with paperwork
A local number in another country is the first thing to sort out, and most countries want to know who you are before you get one. Twilio's regulatory guidelines list, for dozens of countries, which number types it sells there and which address and identity documents each type needs. Some ask for a local business address. Others ask for proof of who runs the account.
Plan for this before the campaign date. The number goes live only after the carrier approves the documents, and a mobile number can need different papers from a landline number in the same country.
Dograh adds a check of its own at this point. When you add a number to a telephony configuration, Dograh asks the carrier whether your account owns it and refuses any number it does not. So the number has to be live on the carrier first, papers and all.
Once it is, numbers in several countries can point at the same agent. The number the caller dialled reaches Pre-Call Data Fetch as to_number, so one agent can tell which country's line rang and load the right details before it speaks.
Caller ID has to be a number you own
Carriers check the caller ID on every outbound call before it leaves their network. Telnyx's caller ID policy rejects a call whose caller ID is not a valid number. When you call outside your profile's home country, the number must also be in E.164 format, the full international form with a plus sign and country code, such as +44207946XXXX.
The safe habit is to show only numbers your carrier issued to you, in the country you are calling. A London number on a US account works when the carrier sold it to you. A London number typed into the caller ID field because it looks local does not.
On a carrier trunk connected through Dograh's Managed SIP, every outbound call carries a caller ID from the numbers on that trunk, and you mark one as the default. For how US carriers label calls once they arrive, see our post on STIR/SHAKEN and caller ID.
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UK and India rules for calls across borders
Some countries now treat a local caller ID arriving from abroad as a warning sign. Ofcom, the UK communications regulator, already expects UK networks to block calls from abroad that show a UK landline number.
Its statement on tackling scam calls from abroad goes further. From 15 July 2027, calls from abroad that show a UK mobile number will reach people with the number withheld, unless they arrive over a route that proves they are genuine. The same statement restates General Condition C6.6, which requires providers to look for calls whose caller ID is invalid, does not identify the caller or cannot be dialled back, and to stop them connecting.
For an agent calling UK customers, this generally means a UK number only works as caller ID on a carrier that places the call inside the UK network. Showing a UK number on a call handed in from another country will be blocked, or arrive withheld.
India splits calls by purpose. TRAI's press release 91/2026 says firms regulated by the Reserve Bank of India (RBI), the Securities and Exchange Board of India (SEBI), the Insurance Regulatory and Development Authority of India (IRDAI) and the Pension Fund Regulatory and Development Authority (PFRDA) must make service and transaction calls to existing customers from 1600 series numbers.
Promotional calls from any sector must come from 140 series numbers registered with a telecom provider under the Telecom Commercial Communications Customer Preference Regulations (TCCCPR). People who block a sector on the Do Not Disturb registry get none of its 140 calls. A bank's payment reminder agent therefore needs a 1600 number, and a sales agent a registered 140 number. Check how these rules apply to your calls with counsel before launch.
Germany and Spain have their own caller ID rules, covered in our post on outbound calling in Germany and Spain. Consent and calling hours are a separate layer, and our post on outbound calling rules for voice agents covers them.
Carrier settings that stop calls going out
Your carrier account decides which countries you can call at all, and the default is often narrower than teams expect. Telnyx's outbound voice profiles hold a list of allowed destination countries, a limit on calls at once and a daily spend limit. A call to a country that is not on the list never leaves Telnyx, however good the agent is.
Plivo's Geo Permissions, under Voice in its console, work the same way. A pay-as-you-go Plivo account can switch on outbound calls to the US and India only, and other countries need an upgraded account.
So when a campaign shows every call to one country failing in the first second, check these settings before you touch the prompt. The agent never got a chance to speak.
Regions, time zones and data in Dograh
The agent side has its own settings that change by country, and the region comes first. Dograh's Managed SIP domain has Global, India and UAE edges, and you pick the one closest to your carrier's servers to keep the audio path short.
Next comes the carrier itself. One organization can hold several outbound trunks, each with its own region and numbers, so a UK carrier can carry UK calls and an Indian carrier Indian calls for the same agent.
Time matters as much. A campaign's calling hours run in one time zone, UTC by default, so split the list by country and give each campaign its own zone. A single list across London and Mumbai would ring one of them at the wrong hour.
Where call data must stay in one country, self-host the platform on servers there and run the speech and language models there too. Self-hosted Dograh has no per-minute platform fee, but servers, model keys and phone minutes still cost money. Dograh Cloud charges a 1¢-a-minute platform fee.
Local numbers also change who picks up, and our post on why AI outbound calls go unanswered covers answer rates in detail.
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Glossary
- E.164
- The international phone number format: a plus sign, the country code and the national number, with no spaces. Carriers such as Telnyx require it for caller ID when a call goes outside the account's home country.
- Calling line identification (CLI)
- The caller ID data that travels with a call. Ofcom's General Condition C6.6 requires UK providers to stop calls whose CLI is invalid, does not identify the caller or cannot be dialled back.
- Geo permissions
- A carrier account setting that lists which countries you may call. Plivo calls it Geo Permissions and Telnyx keeps it in outbound voice profiles, and a call to a country not on the list does not go out.
- 1600 series
- The Indian number range TRAI requires for service and transaction calls from firms regulated by RBI, SEBI, IRDAI and PFRDA to existing customers. Promotional calls use the separate 140 series.
