Wikipedia
Celcom Axiata Berhad, DBA Celcom, is the oldest mobile telecommunications provider in Malaysia. Celcom is a member of the Axiata group of companies. Being one of the very few companies in Malaysia to originally obtain a cellular phone license, it successfully introduced mobile telephony in Malaysia through its ART-900 (Automatic Radio Telephone) service, using first generation (analogue) ETACS (Extended Total Access Communication System) specifications of the United Kingdom, a derivative of the US-AMPS (Advanced Mobile Phone System) technology. The ETACS ART-900 was started using the prefix "010". Celcom now uses the dialling prefix identifier of "013" and "019" and offer digital GSM (Groupe Speciale Mobile), an originally European standard, now largely a world standard for mobile communications. The original frequency band for GSM is 900 MHz, and was soon extended to 1800 MHz to cater for a much wider bandwidth requirements. The 2100 MHz band is used for their dual-channel HSPA+ network. Celcom is also licensed and has been operating FDD-LTE on 1800 MHz and 2600 MHz.
Through the Mobile Numbering Portability by the Malaysian Communications and Multimedia Commission, CELCOM also provides Virtual Mobile Operator services. Celcom also provides rural communications services using CDMA Technology and Satellite Phone.