Telcos have sought parity with over-the-top (OTT) players that provide communications services such as WhatsApp and Skype, saying these apps provide similar services such as voice calling and should be brought under the same regulation as carriers. "It is an undisputed fact that VoIP (voice over Internet protocol) service offered by OCSPs (OTT communication service providers) is a substitute for" services offered by telecom service providers (TSPs), Rajan Mathews, director general at GSM industry body Cellular Operators Association of India (COAI), said in a letter to the telecom regulator dated June 3.

COAI said in its latest letter. It noted that mobile phone operators realise only around a sixth from a data call made over the communications apps compared to what they realise from a normal voice call.

"The low data price is furthering the growth of VoIP/Internet telephony by unlicensed OCSPs at the cost of PSTN voice telephony, thereby reducing TSPs ability to continue with the lower price of data for accessing content over the Internet," said COAI.

COAI added that Trai also needs to address the issues surrounding termination charges from calls from a communication app to a regular cellular network, but keep in mind the ongoing court cases around the issue of termination charges.

Issues such as allocation of a separate number series for Internet traffic, security, lawful interception, quality of service need to be sorted out before "termination of Internet telephony calls is facilitated in PSTN/PLMN network".