We are here to help you get answers to your questions about OneSimCard phones and services.
What Is the Difference Between "Direct Dial" and "Callback Dial" calling?
Direct Dial calling allows the caller to enter the international call prefix, country calling code and telephone number and then be directly connected to the person they are calling. This is how you dial when using your regular mobile service. Direct Dial Calling is standard on the OneSimCard Europe & More, OneSimCard Universal and eSIM.
Callback calling also allows the caller to enter the international call prefix, country calling code and telephone number. After the called number is entered, the user immediately receives an incoming call connecting the user to person called. Callback is very simple to use and allows for low cost calling on the OneSimCard Plus and OneSimCard Expedition (formerly Data & Roam). Callback does not increase the connection time. It is the same as with Direct Dial.
When I dial following your instructions it does not work. What's wrong?
This answer applies to SIM cards purchased before January 1, 2017.
Some phones, such as Samsung, some Motorola, Android and Apple iPhones, require special dialing instructions or simple OneSimCard settings menu changes in order to make calls.
It is possible to make almost any phone entirely compatible, so you can call directly without using the OneSimCard menu or *146* by following these simple programming instructions below.
How to activate compatibility mode:
 1. Locate OneSimCard Menu.
 On iPhones it is called SIM Applications menu and is located under Settings- Phone menu
     On Androids it is called SIM Toolkit app or OneSimCard app and it looks like one of the apps.
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Bear in mind that if you have powered your telephone down, and have removed and reinstalled the battery, you will need to follow the programming steps outlined above, again.
If for any reason after entering compatibility code, you still do not get a ringback or you get the ringback the first time you make a call, but second time it would not work, please enter code 802 into the Service Code window instead of 1101 as provided above.
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iPhone users can download OneSimCard Assist App from iTunes that will takes care of the iphones compatibility issues, except for removing the ringback.
For example, calling to USA:Â Dial *146*0016175551212# and press the TALK (or SEND) button
The sequence *146* and # at the end can be used from any phone. However, most phones do not require it.
We strongly recommend you to watch very short video tutorials that will help you to understand how to make calls, SMS and data on your OneSimCard Phone.
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Can I use Facetime, WhatsApp, Telegram, Discord, iMessage, and other messaging Apps with eSIM?
For DataMax eSIM, you can use these Apps as you already do. Please ensure your messaging account is already setup with your primary carrier’s phone number because you cannot sign up for these services with the DataMax eSIM number.
Additionally, the eSIM data service can be used for the actual data part of your communications. So, when you are installing eSIM on phone, you can select the Primary service for Facetime and iMessage and then if your selected eSIM to be your primary data service, the communications will go over eSIM mobile data.
Is text messaging available on the OneSim VoIP App?
OneSimCard SIM VoIP users with US and Canadian numbers may now send and receive text messages over the OneSim VoIP app on iPhone and Android. The cost to sending a message is $0.05 per text to most countries. Receiving message is $0.05. Â
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OneSimCard SIM VoIP users with US and Canadian numbers may now send and receive text messages over the OneSim VoIP app on iPhone. The cost to send or receive each message is $0.05.Â
I am traveling in Saudi Arabia and can receive calls, but I can't make an outgoing call. What should I do?
Local carriers in Saudi Arabia sometimes block standard OneSimCard outgoing calls. If this happens you need to either (a) enter a compatibility code into the settings of your phone or (b) initiate your call by sending an SMS message from the regular SMS menu (not the OneSimCard menu) of your phone.
How To Activate Compatibility Mode:
Bear in mind that if you have powered your telephone down and removed and reinstalled the battery, you will need to follow the programming steps outlined above again.
How To Deactivate Compatibility Mode:
How To Dial Without Activating Compatibility Mode:
Initiate your call by sending an SMS message from the regular SMS menu (not the OneSimCard menu) of your phone.
For example, to call from Saudi Arabia to Boston USA you should go to the SMS menu of the phone and send a message:
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There are no special instructions to receive calls in these countries.
When I try to make a call, I get a message 'Call is modified and cannot be made'. What does that mean?
Some phone models do not allow direct dialing with older OneSimCard SIMs sold before January 1, 2017.
To get around this problem, you should try either of these methods:
* is a star character located on the keypad
Other examples of how to use the *146* dialing prefix if necessary:
The prefix *146* and # at the end can be used from any phone. However, newer OneSimCard SIM do not require it and you should be able to dial codes directly, 091, 094, 095, 099 or 098XXXX*XX Talk.
If you have an older SIM and the dialing does not work without entering *146*, please follow these simple instructions to remove the need to dial *146*:
How to activate compatibility mode:
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 1. Locate OneSimCard Menu.
 On iPhones it is called SIM Applications menu and is located under Settings- Phone menu
     On Androids it is called SIM Toolkit app and it looks like one of the apps
Newer SIM Cards: Select Compatibility option and make sure "On" is selected
Older SIM Cards: After selecting Settings:
Bear in mind that if you have powered your telephone down, and have removed and reinstalled the battery, you will need to follow the programming steps outlined above, again.
When dialed directly, some Nokia and other phones can display message: "Call is not allowed" or "Call is barred". Just ignore this message and wait for the ring-back for 10 seconds or so.
How do I enable roaming on my Android Phone?
This is very simple!ÂWill a OneSimCard international SIM card work with my mobile phone?
OneSimCard will work with almost any unlocked GSM tri-band or quad-band cell phone. A partial list of compatible cell phones that we have tested can be viewed here.
If you need to unlock the phone, we suggest contacting your carrier or phone manufacturer for unlocking information or services.
If your phone is not a quad-band phone, please make sure that the bands of your phone are those required in the country of your travel. You can look it up here.
If you are still unsure whether your cell phone is compatible, contact support or purchase an international cell phone and SIM card bundle from us, which all come preloaded with our international SIM card, $10 balance and OneSimCard Apps Installed.
I have more than one Personal Extra Number (PEN). Can I use different PENs for OneSim VoIP?
If you have more than one OneSim VoIP enabled PEN you can switch between these PENs for the purpose of the OneSim VoIP account. This option is available in the My SIM Cards menu in your online account.© 2006-2024 Belmont Telecom Inc., DBA OneSimCard.com. All rights reserved