International Call Limitations and Risks
This article will explore the restrictions in place for dialing internationally to reduce the risk of fraud and paying high tolls.
Written by Adrian Angwenyi
Updated at March 31st, 2023
Table of Contents
To view our list of how to dial internationally and our accepted International Country Codes for dialing, check out this article.
WARNING: By default, SpectrumVoIP phones have international dialing Disabled in order to prevent accidental international fee fraud.
Please contact Technical Support if you would like International Calls Enabled on your phone.
There is no charge to enable International Calling. International Calling fees only occur when International Calls are placed.
NOTE: SpectrumVoIP may disable the ability to call certain global regions due to high fraud risk or if the rate is higher than our threshold.
This is all in order to try to prevent fraudulent calls from happening.
Blocked Countries
There are countries that we block and will not unblock due to fraud and high tolls.
According to the recommendations of Bandwidth, SpectrumVoIP blocks the following frequently “Fraudulent” countries from being dialed:
- AC Ascension Islands 247
- AG Antigua/Barbuda 268
- AI Anguilla 264
- AS American Samoa 684
- BB Barbados 246
- BM Bermuda 441
- BS Bahamas 242
- CD Democratic Republic of the Congo 243
- CF Central African Republic 236
- CG Congo 242
- CZ Czech Republic 240
- DM Dominica 767
- DO Dominican Republic 809 829 849
- GD Grenada 473
- GQ Equatorial Guinea 240
- GU Guam 671
- HT Haiti 509
- JM Jamaica 876
- KN St. Kitts & Nevis 869
- KY Cayman Islands 345
- LC St. Lucia 758
- LT Lithuania 370
- MA Morocco 212
- MF St Martin 590
- MP Northern Mariana Islands 670
- MS Montserrat 664
- MV Maldives 960
- PK Pakistan 92
- PW Palau 680
- SC Seychelles 248
- SX Sint Maarten 721
- TC Turks and Caicos Islands 649
- TD Chad 235
- TN Tunisia 216
- TT Trinidad and Tobago 868
- UG Uganda 256
- VC Saint Vincent and the Grenadines 784
- VG British Virgin Islands 284
- VI U.S. Virgin Islands 340
- SL Sierra Leone 232
- SD Sudan 249
- LR Liberia 231
- LV Latvia 371
Types of Telecom Fraud
While there are almost too many different types of telecom fraud to list them all, there are five (5) main types that we, and our users, see most often:
- International Revenue Sharing Fraud (IRSF)
- Traffic Pumping
- Domestic Premium Rate Service
- Interconnect Bypass
-
Telecom Arbitrage (Tromboning)
International Revenue Sharing Fraud (IRSF)
International Revenue Sharing Fraud utilizes technical means to make unauthorized calls to premium numbers with high tolls/fees. To do this, cybercriminals and fraudsters use hacked IP phones, stolen SIM cards, and compromised Public Branch Exchanges (PBXs) to direct calls to their own or leased lines to bill those incoming calls.
To prevent these kinds of attacks, passwords for the IP phones' web user interfaces are not handed out unless certain special conditions are met by the requester for this information.
Domestic Premium Rate Service
Much like IRSF, Domestic Premium Rate Service relies on parts of the U.S. being more expensive to complete calls to.
Rural parts of the country can be more expensive to call, so fraudsters commonly use this to intercept and route calls to these more expensive areas to collect larger fees.
Traffic Pumping
Traffic pumping happens when fraudsters utilize automated phone-answering services to generate traffic in expensive areas of the country to complete calls. They then advertise these numbers (often via social media) to drive calls into their system.
Callers are met with dead air, barking dogs, or ‘press 1 to continue’ loops to extend the length of the call to maximize the amount of money they can charge for these calls.
Sometimes a nefarious service provider could be involved. These bad actors will overcharge reputable carriers with exaggerated access charges with a portion of these fees given to the fraudster.
Telecom Arbitrage (Tromboning)
Telecom Arbitrage, also referred to as “Tromboning”, happens when telecom companies utilize and provide long-distance access numbers that route calls through a third country as a middleman in order to falsely present themselves as offering lower settlement rates to attract customers.
What these customers do not realize is that this strategy earns the telecom company higher interconnect fees while also putting the customer at risk for fraud and unwanted robocalling.
Operators can combat telecom arbitrage by ensuring they only resell minutes to reputable companies and keep a close eye on their partnerships with third parties.
Interconnect Bypass
Also referred to as OTT Bypass Fraud, interconnect bypass fraud is based on legacy interconnect telecom systems. Fraudsters will sell long-distance calling cards to be used by unsuspecting customers. When a customer calls this number provided to them, their call is redirected to another Carrier's network to make the call appear like a cheaper, domestic call to bypass the normal payment system for international calling. In reality, the Carriers that are given this redirected traffic take on those fees/tolls.
Due to how this fraudulent activity works, customers are not usually impacted since the affected carrier ends up accepting the fraudulent charges.