What INS Net Was
NTT's INS Net (Integrated Services Network) was an ISDN digital communications service launched in 1988. It allowed two simultaneous calls or one call plus data transmission per line - cutting-edge for its time and adopted across business phone, fax, banking terminals, and POS infrastructure. At peak, around 8.5 million lines were in use, making INS a backbone of Japanese business communications. Networking primers provide useful context.
The January 2024 Migration
NTT completed its PSTN (Public Switched Telephone Network) migration to IP networks in January 2024, fundamentally changing INS Net's positioning.
Continuing services
- Voice and fax continue as "INS Net (complementary service)" over the IP network
- Existing phone numbers (03-XXXX-XXXX, etc.) remain usable
- Two simultaneous calls per line is preserved
Discontinued services
- Digital communication mode (dedicated data transmission)
- Packet communication
- Specific protocol connections to communications equipment
- Data-related supplementary services (high-speed digital mode, etc.)
Affected Business Operations
1. Banking and financial dedicated terminals
ATM communications, POS sales data transmission, and inter-company dedicated lines that relied on INS data transmission needed migration to IP-VPN or dedicated lines. Most financial institutions completed the switch before the deadline.
2. EDI (Electronic Data Interchange) systems
Some manufacturer/distributor EDI for ordering and delivery exchanges depended on INS data transmission. These are migrating to Web-EDI, AS2, and dedicated lines.
3. Security company remote monitoring
Security systems from SECOM, ALSOK, and others that transmitted incident reports from contracted homes and stores via INS have been updated to IP-network-based systems.
4. Remote medical-device monitoring
Some dialysis machines, pacemakers, and home medical devices using INS for remote monitoring also migrated to IP networks.
Migration Options
Voice and fax only
You can continue using INS Net as a complementary service - call quality routes via IP, but no user-side switching is required. Monthly fees are roughly equivalent, and no procedure is needed.
Data transmission needs
- IP-VPN: Most common dedicated-line option for inter-company / inter-site connections; tens of thousands of yen monthly
- Internet VPN: Cost-effective option leveraging existing internet
- Dedicated lines (including dark fiber): For large-scale, high-security operations
- Mobile lines (LTE/5G routers): Rapidly growing as POS and payment-terminal alternatives
Cloud-based EDI
Exchange data via cloud platforms instead of direct partner connections. As a modern business communication option, this dramatically reduces operating costs.
Migration Considerations
1. Verify business-system compatibility
Long-running systems may not work over IP networks, requiring hardware updates. Old banking terminals, POS, and dedicated EDI machines should be checked with vendors.
2. Validate communication quality
Fax over IP is more prone to delays and packet loss, raising send/receive error rates. For mission-critical fax operations, run test transmissions after migration. As covered in Hikari Denwa migration guide, fax requires careful attention.
3. Reassess security requirements
Switching from dedicated lines to IP-VPN or internet VPN requires reviewing encryption and authentication. Financial and medical institutions need confirmed compliance with industry standards.
4. Cost structure shifts
You may move from usage-based to flat rates or vice versa. Calculate annual total cost before selecting your migration target.
Impact on Sole Proprietors and SMBs
If you only use voice and fax, INS Net (complementary service) continues with no special action needed. If you used data transmission, choose a migration target that fits your operations. Stores using credit-card terminals can substitute modern mobile payment terminals (such as mobile payment terminals) to complete the INS replacement.
The Future Direction of Phone Infrastructure
INS Net's phased retirement symbolizes Japan's complete migration to integrated IP networks. Going forward, cloud PBX, VoIP, and SIP trunking technologies dominate, and the technical lines between landline, mobile, and data communication blur. From the user's perspective, however, "phone numbers," "fax," and "dedicated lines" remain meaningful concepts - so it's important to operate with awareness of the technology-vs-usage gap.