Telecommunications Regulatory Commission of Sri Lanka


TRCSL manages the National Numbering Plan for the telecommunications sector in Sri Lanka including the allocation of numbering resource. The Numbering Plan provides the framework and guidelines for the use of numbering resource.

National Numbering Plan

Short Codes


VOIP Unblocking

VOIP is not allowed in Sri Lanka for the purpose of to by-pass international telecommunications services under theTelecommunications Act No 25 of 1991 and its amendment Act No 27 of 1996. Therefore the following VOIP applications are blocked by all the operators.
But, since we understand the importance of using VOIP by the enterprises, TRCSL has decided to allow the categories of users / customers / clients to claim unblocking of VOIP application.

Technical Parameters to block the VOIP application

No Technical Parameters / Conditions Description
01 Type of connection

Symmetric broadband, leased line, international Private leases circuit except asymmetric broadband

Connections using technologies like ADSL,GPRS,3G,HSPA,Wimax etc

02 Bandwidth ≥ 1Mbps
03 Protocol/Application VOIP related application, protocol, ports etc. Suspected to be used for illegal bypass such as SIP H.323,IAZ.RTP,MGCP.H.248,Megaco,SCCP,and it’s associated ports like H323 (TCP1720),SIP (TCP/UDP 5060-5061)

Categories of users/customers/clients eligible to claim unblocking or exemption from the blocking of VOIP application

  1. Licensed PSTN Operators
  2. An EGO operator who has obtained an interconnection from the PSTN operators and the interconnection is in operation subject to verification from the TRCSL
  3. Licensed ISPs subject to verification from the TRCSL
  4. Authorized call centers or BPOs approved by the TRCSL
  5. Any customer who communicate with his own officers within the country.
  6. Any customer who is handling international logistics, International banking and IT/Software development and support service etc
  7. Any customer who uses above listed protocols/ports for any other application which is not used to establish and terminate illegal voice bypass subject to verification from TRCSL

Procedure of Activation of VOIP facilities

  1. The Application Form must be perfected and then handover by the customer via the respective operators to TRCSL with sufficient reasons supporting the request to unblock the VOIP
  2. Once approval is granted by TRCSL the original document will be sent to the service provider with a copy to the customer
  3. The customer list shall be used by the TRCSL only in respect to activities related to the international voice call bypass network
  4. The customer shall be monitored by TRCSL to ensure that they comply with the conditions of approval.