China Telecommunications Regulatory & Interconnect Guide: MIIT A2P SMS & Voice Rules

Telecommunications services in mainland China (+86) operate under the central regulatory oversight of the Ministry of Industry and Information Technology (MIIT). Unlike open Western telecommunications markets where dynamic caller IDs and unverified SMS sender IDs are handled via soft carrier filters, mainland China strictly regulates all cross-border messaging and voice traffic.

Under Chinese telecom law, domestic telecommunications infrastructure is operated by state-licensed mobile network operators (MNOs): China Mobile (中国移动), China Telecom (中国电信), China Unicom (中国联通), and China Broadnet (中国广电). International carriers like AVM Networks Limited terminate traffic through direct bilateral interconnections with licensed international gateway entities, ensuring full compliance with national security guidelines and consumer protection laws.

Mainland China does not support dynamic alphanumeric sender IDs (such as "MyCompany"). Instead, all A2P SMS messages must include a pre-registered enterprise signature enclosed in Chinese full-width Unicode brackets (e.g., 【CompanyBrand】).

Key requirements for signature brackets and message templates include:

- Format & Encoding: Signatures must use full-width Chinese brackets 【 】 (Unicode U+3010 and U+3011). Half-width square brackets [ ] will result in operator rejection.

- Length & Content: Signatures must be 2 to 12 characters, representing the legal business name, registered trademark, or official app name of the sending enterprise.

- Business License Verification: Enterprise registration requires submitting a valid Certificate of Incorporation (or Unified Social Credit Code for PRC entities) alongside an official power-of-attorney authorization letter.

- Variable Templates: All transactional messages (2FA OTP, order status) must be registered as parametric templates with fixed text and defined placeholder variables ({1}, {2}).

Effective December 1, 2022, the Anti-Telecom and Online Fraud Law of the PRC (中华人民共和国反电信网络诈骗法) established strict statutory penalties for telecommunications operators facilitating illegal caller ID spoofing, fraudulent robocalling, or unauthorized cross-border voice bypass.

In compliance with this legislation, AVM Networks enforces strict technical standards across its China voice interconnects:

- Mandatory E.164 CLI Pass-Through: All calls terminating into mainland China (+86) must transmit fully authentic, non-spoofed ITU-T E.164 caller identification.

- Automatic Spoofing Blocking: Gateway anti-fraud filters reject any international call presenting a domestic Chinese subscriber number unless backed by verified carrier enterprise documentation.

- Prohibited Routing Categories: Non-CLI, NCLI, CLI manipulation, and grey routing are strictly forbidden across all AVM Networks peering interconnections.

For high-volume enterprise communications, AVM Networks provides direct SMPP v3.4 transceiver binds and SIP v2.0 (RFC 3261) trunks hosted at regional carrier peering facilities in Hong Kong (Equinix HK1, Mega-i) and Singapore (Equinix SG1).

- SMPP Messaging Binds: Supports multi-bind asynchronous sessions handling high-volume TPS per account, with automatic UCS2/GBK encoding handling, concatenated UDH assembly, and immediate handset DLR callbacks.

- SIP Voice Peering: Supports G.711a (PCMA) and G.729a codecs with TLS signaling encryption and SRTP media payload encryption, ensuring low Post Dial Delay (PDD) and carrier-grade voice quality.