In the past, when you call an office building or business, you would either be transferred to the department you want to talk to, or given their extension number. This extension is usually a 2-3 digit code that when dialed, transfers you automatically to the particular person or department you want to speak with. The reason why this code works is because it is programmed into a PBX system.
Persia Telecom Co. is a subsidiary of IOEC (Iranian Offshore Engineering & Construction Company) in Islamic Republic of Iran that was established in 2004.
IOEC is the 1st Iranian general contractor in the Oil & Gas industry.