Colt Voice Services

Colt offers a range of high quality, reliable ISDN/PRI and IP-based voice services in Japan for enterprise and wholesale customers. Delivered over Colt’s reliable and secure ultra low latency fibre optical network, Colt VoiceLINE is capable of carrying integrated voice and data calls to and from domestic, international, mobile, and 0120 toll-free numbers to ensure high quality voice communications.

Colt VoiceLINE provides a high-quality, dedicated, and direct connection to your PBX. It smoothly handles incoming, outgoing, domestic, and international calls between landline, mobile and IP phones. The service is offered in the greater Tokyo and Osaka areas, and can be ISDN or IP-based to match your system requirements. Whether you go with ISDN or IP, VoiceLINE allows you to keep existing NTT ISDN/analog phone numbers through number portability or acquire new Colt phone numbers.


VoiceLINE ISDN Service

  • Capacity: 23 simultaneous calls for each T1 access circuit via PRI (Primary Rate Interface)
  • Availability: Tokyo (03), Tama (042), Yokohama (045), Kawasaki (044), Chiba (043), Narita (0476), Urawa (048), Kawaguchi (048), Osaka (06), and Kobe (078)


VoiceLINE IP (VoIP) Service

  • Capacity: 8 simultaneous call channels for each 10Base/100Base circuit using SIP
  • Availability: Tokyo (03), Tama (042), Yokohama (045), Kawasaki (044), Chiba (043), Narita (0476), Urawa (048), Kawaguchi (048), Osaka (06), and Kobe (078)
  • Minimum of 8 channels


Customer Benefits

High Quality

Delivered over Colt’s self-healing fibre network and high-quality interconnections with other carriers

Broad Coverage

Can terminate all traffic types, including fixed, mobile, and 0120 toll-free numbers, and to all local, domestic, and international destinations

Competitive Pricing

Up to 40% less expensive than other Japanese carriers’ voice services

Fast Provisioning Time

Less than 1.5 months for new customers and two weeks for Colt data services customers

Flexible Pricing Options

Variety of billing intervals (1 sec, 1 min, 3 min) and pricing plans available for both domestic and international calls

Business Continuity

Optional DR service automatically routes calls to pre-registered destinations in the event of a PBX power cut or traffic overflow

Full Support

Comprehensive 24×7 monitoring and bilingual customer support in English and Japanese with dispatch maintenance service available 24x7x365

Scalable Channels

Additional voice channels can be added over the existing circuit for rapid scalability at a very reasonable cost

Prevention of Fraudulent Use of Voice Calls by Third Parties