List of facilities based operator:
www.imda.gov.sg/regulations-licensing-and-consultations/licensing/licensees/facilities-based-operator

List of Telecommunication System Licensees to be Consulted/Notified for Earthwork:
www.imda.gov.sg/regulations-licensing-and-consultations/licensing/licences/licence-for-provision-of-service-of-detecting-underground-telecommunication-cable