SMS and Call Known Limitations

This page lists all known limitations for the SMS and Call services. Please be guided accordingly.

SMS Char Limit

In CINNOX, a single (1) SMS is limited to 160 chars for English text, while 70 chars for non-English text (universal code) like Chinese and Japanese scripts.

If the SMS text exceeds the single SMS limit, it splits into smaller messages for transmission.

  • A. SMS with English chars > 160 splits into 153-char per sent.
    E.g., an SMS with 161 chars - will be sent as 2 SMS, first with 153 chars and the second with 8 chars.
  • B. SMS with non-English chars > 70 splits into 67-char per sent.
    E.g., an SMS with 71 chars - will be sent as 2 SMS, first with 67 chars and the second with 4 chars.
  • C. When an SMS is combined with English and non-English chars, 1 non-English char is regarded as a non-English text.


SMS with URL Content

Some countries do not allow sending an SMS with URL content (e.g. Mainland China (+86) & Taiwan (+886)). The SMS can be sent out but may not be delivered.



SMS may not be delivered to a Non-Mobile Number

Please ensure that your phone number recipient is a mobile number. A non-mobile number may not be able to receive SMS messages. A warning is displayed in the dialogue window when a phone number is non-mobile or invalid.



Sending SMS to Mainland China number (+86)

According to the regulations and requirements of the China carrier, you must register a template with the carrier to send an SMS to a mainland China number (+86). The registered template will only be delivered if the SMS content matches exactly. Suppose you still send SMS with the content without a registered template, or the actual content does not match 100% with the registered template (e.g. a variable field containing an index filled with a string). In that case, it will be sent out but void and incur a cost.Please contact your account manager to learn more about the procedure and requirements for registering a carrier template.


Other Notices

All message templates must be authorised and registered through CINNOX, so customers must prepare the "Letter of Authorisation" for the template application. Please get in touch with your account manager for more details about the "Letter of Authorisation".

  • The A2P SMS sent to China shall comply with the "Terms of Acceptance by the User for A2P SMS". Please get in touch with your account manager for more details about compliance with the "Terms of Acceptance by the User for A2P SMS".
  • Sending SMS with an alphanumeric address is prohibited.
  • Sending SMS with the numeric address and the prefix "+852" is preferred.
  • Delivery of SMS messages containing web links to China is prohibited.
  • The sender ID is not guaranteed to be displayed to the message recipients.


Terms of Acceptance by the Users for A2P SMS Delivery to China (Excerpted version)

Users are responsible for the authenticity, accuracy and legitimacy of sent information. SMS is filtered out sensitive information with a violation of law and regulations; the information may not contain SMS message content with any one of the following:

  1. Users will not use the SMS service with message content to spread information which may harm social security, spread superstitious, feudal and pornographic information; steal or disclose national secrets, intelligence, or military secrets; stir national hatred and discrimination; undermine the ethnic solidarity, organise cult activities, liaison with cult members to breach state laws or regulations.

  2. 9 prohibited SMS Messages standards:
    • Political news;
    • Harm social security;
    • Steal or disclose national secrets;
    • Breach state laws or regulations;
    • Feudal and pornographic information;
    • Spread the superstitions;
    • Gambling;
    • Fake or invalid information;
    • Destroy the morality of society and Legitimate Rights and Interests;

  3. 5 prohibited information categories:
    • Fraud and extortion by using fake names;
    • Spread pornography, gambling, violence, homicide, terror or instigate crimes, impact criminal methods;
    • Illegal sales of firearms, ammunition, explosives, smuggling, drugs, ecstasy, pornography, and banknote that is known to be fake or swag;
    • Distribution of fake lottery, fake marriage, fake recruitment, lure or introduce prostitution;
    • Disturb others by repeatedly sending SMS or prohibited information which violates laws and regulations;

  4. Users will not use the SMS service for advertising, spam, fraud or unsolicited messages; Users are permitted to send one-time notification message type only (e.g. verification code, notification or reminder, etc.)

  5. User must comply with provisions of intellectual property rights and agrees not to transmit or disseminate material data that infringes or violates any third party's intellectual property rights, including patent, copyright, trademark, or trade asset, rights of publicity, privacy, or confidentially, or the rights or legal obligations of any wireless service provider or any of its customers or subscribers.6. User will not use the SMS service for sending viruses, Trojan horses, worms, or other computer programming routines that are intended to damage, interface with, intercept or expropriate any system, data, or personal information, or any signal or impulse that could cause electrical, magnetic, optical, or other technical harm to the equipment or facilities of any involved parties or any third party.


Sender ID and Caller ID (CLI) is not guaranteed to be displayed

Due to telecom regulations varying from place to place, Service Numbers set as a Caller ID (CLI) or SMS Sender ID are not guaranteed to be displayed to recipients.


Caller ID


Local Number Caller ID Displays Country Code

CINNOX International Direct Dial (IDD) calls to some regions and countries display country codes even when calling to the same region and country. This rule depends on the regions' and countries' telecommunications policies.



Web Platform Call Known Issues

In-Call Advertisement Video:

  • For iOS devices, all browsers require audio and video resources to be played only upon user interaction, meaning the user needs to click to play video ads during the waiting time of the call.

Video Call Functionality:

  • Some Huawei Android devices cannot support H.264 encoding and decoding capabilities, so video functionality is not supported in the Web browser and Mobile App.

Voice Functionality (Voice, Video, Conferencing, Screen Sharing, Voice Message Recording):

  • Vivo Android devices' built-in browsers do not support WebRTC basic capabilities, so the calling function is not available.
  • Xiaomi Android devices' built-in Xiaomi browser does not support WebRTC basic capabilities, so the calling function is not available.

Restricted Call Scenarios

The following countries have some call restrictions depending on their local telecommunications policies.

AustraliaCalling in Australia with the following categories will be blocked by Australian Carriers.

- No CLI
- Invalid CLI (A-number which does not conform to international standards (ITU-T Recommendation E164), or is an invalid number length, or is a dummy CLI)
- Calls with an Australian A-number (+61), except for international roaming numbers. Calls with +61 A-numbers can only be legitimately sent on Australian domestic switches.
- alls with an Australian domestic Free call or other inbound calling numbers as CLI
- Calls with a CLI that is known to be a source of scam calls
FijiThe Fiji Toll-Free number can only be connected with callers using a landline number. It is not supported for callers using a mobile phone.
FranceCalling numbers from the international with a CLI or Protocol Addressing Information (PAI) or Personally Identifiable Information (PPI) or RPI or Calling Party Number or Generic Number) starting with +33 1/+33 2/ +33 3/ +33 4/ +33 5 and +33 9 and toward a called number
starting with + 33 (excepted MSRN ranges +33 653/ +33 654/+33 655 will be systematically filtered.
Hong KongCalling Hong Kong IDD using Hong Kong fixed line number CLI is not allowed. Hong Kong mobile numbers beginning with 8524, 8525, 8526, 8529, and part of 8527 and 8528 CLI are allowed.

Calling Hong Kong DID from overseas will replace the CLI with ANONYMOUS or a particular Hong Kong number.
IndiaCalling a number +91, using a fixed line +91, is restricted per the India Department of Telecommunication (DOT) Guidelines.
IndonesiaCalling a fixed line number +62 using fixed line +62 is not allowed.

- International Direct Dialling (IDD) using 001, 008, 007, etc
- 001 803 is International Toll-Free (ITF), and 0800 is Domestic Toll-Free.
- IDD services must be activated to dial even local callers for international toll-free numbers.
JapanThe CLI +81 for domestic mobile networks will be removed during international calls.
For a landline, it depends on the carrier to which the call terminates. Most carriers block the CLI when it is an international call starting with +81.
This is the policy to prevent fraud calls.
Mainland ChinaCalling in Mainland China is not allowed for the following:

- China termination calls
- Without caller number
- Invalid caller number
- Caller number with NOA=national
- Caller number with number incomplete (NI=1)
- Caller number with presentation restricted (PI=1)
- Caller number starts with 86(1-9)fixed number (86 calling 86)
- False roaming caller starts with 861 mobile number
- A number frequently calling in a short time.
- A caller number is your own number, aka Bring Your Own Number (BYON)

Calling in Mainland China is considered abnormal and may be blocked by the China local operators for the following:

- 4001 China toll-free cannot be used as a Calling Line Identity (CLI)
- The caller number is too short or longer than 13 digits
- The caller number starts with 0, e.g. 08601321346
- Low Answer Seizure Ratio (ASR) means no unsolicited calls - too many call attempts vs the number of calls getting picked up.
- Low Average Call Duration (ACD) means the average call duration is too short (e.g. all calls are below 1 minute). The typical call duration should be at least 2-3 minutes
- Spam (junk) calls
MalaysiaCalling a number +60, using +60, the traffic is considered a spam call, and it will be blocked by operators. This is also a government regulation to protect their people from fraudulent calls.
PhilippinesCalling a fixed line number +63, using a fixed line +63, is not allowed.
TaiwanCalling the Taiwan Toll-Free number is not guaranteed for callers outside Taiwan.

Criteria must be met to connect the call:
- Automatic Number Identification (ANI) must be Taiwan's number
- Type of Number (TON) must set National
- Numbering Plan Identifier (NPI) set as Integrated Services Digital Network (ISDN)
- No call status on layer3
- Calling the Taiwan IDD using the Taiwan fixed number CLI beginning with 8860 up to 8868 is not allowed.
- You can only make calls to Taiwan numbers via CINNOX using a local termination number. Contact us at [email protected] to obtain a local termination number.
ThailandIn-country call (Calling a number 66, using 66) is not allowed.
This issue is due to the policy of the Thailand National Broadcasting and Telecommunications Commission (NBTC) to block spam calls.
- It blocks incoming calls from international carriers when the calling number is with "Thailand's fixed line number, such as 660, 661, 662, 663, 664, 665, 667, 02, 03, 04, 05, 06, 07".
- It allows incoming calls from international carriers when the number is "Thailand Mobile Station Roaming Number (MSRN)".

Using Thailand mobile number "+66 8" CLI will be replaced with "+698", e.g., +66 82134567 will become +698 82134567
VietnamAccording to local regulations, calling a Vietnam number with international routes is not allowed.