- Bharat Sanchar Nigam Limited (BSNL)
- Mahanagar Telephone Nigam Limited (MTNL)
- ITI Limited
TCIL offers total telecom solutions for projects and has its presence in almost 45 countries mainly in Middle East Africa, South East Africa, South East Asia and Europe. At present the turnover of the company is more than 500 crores.
Delhi State Industrial & Infrastructure Development Corporation a state PSU of Delhi Government is the joint venture partner of TCIL in Intelligent Communication Systems India Ltd.
TCIL-IT, a division of TCIL is managed by Intelligent Communication Systems India Ltd.,( ICSIL)