BT Group PLC
According to its Form 20-F filed with the U.S. SEC on May 31, 2019, "BT has a contract in place with Telecommunication Infrastructure Company (TIC), to make and receive voice calls from Iran to the UK." (SEC, "Form 20-F", 3/31/2019).
In a letter to CalPERs dated November 3, 2017, BT Group confirmed it is not engaged in the business activities targeted by the California Public Divest from Iran Act.
In 2017, the U.S. state of California listed BT on its state list of companies under review for Doing Business with the Iran.
BT lists on its website that it has a sales representative in Iran, Sepahan Lifter Company. (BT website, "About Us, BT in the World")
Sepahan Lifter company lists on its website that it is functioning under a BT Sweden license. (Sepahan Lifter website, "About Us")