- ILS (Instrument Landing System)
- IP-VPNサービス (IP-VPN Service)
- IPアドレス (IP Address)
- IP電話 (IP Telephony)
- IP放送(IP broadcast)
- ISDBファミリー (Integrated Services Digital Broadcasting Family)
- ISM設備(Industrial, Scientific and Medical Equipment)
- ITU(International Telecommunication Union:国際電気通信連合)