Chandigarh: Chandigarh Police have busted a sophisticated SIM box setup that was being used to route Voice over Internet Protocol (VoIP) calls into India’s GSM/LTE network. The operation was allegedly linked to thousands of fraudulent “digital arrest” scam calls, a rising cybercrime tactic that impersonates government or law enforcement authorities to extort victims.
The raided system was found to be equipped with Quectel EC20 LTE cellular modules and multiple SIM cards housed in a rack-mounted configuration. According to investigators, this allowed the perpetrators to mask VoIP-originated calls as local mobile numbers, thereby evading detection and increasing the chances of victims answering the calls.
How the Scam Worked: From VoIP to GSM
Officials explained that the syndicate used Session Initiation Protocol (SIP) to initiate scam calls over the internet. These calls were then converted to GSM/LTE signals through the SIM box, making them appear as though they were made from within India.
This setup enabled mass termination of scam calls without triggering conventional telecom fraud detection systems. Police estimate that lakhs of such fraudulent calls may have been terminated using this single setup, with most victims targeted through threat-based scripts claiming that their bank accounts or identities were linked to criminal cases.
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Public Advisory and Legal Consequences
Authorities have issued a strong public advisory warning citizens to remain vigilant against “digital arrest” scams, in which victims are coerced into transferring money or sharing sensitive data under the threat of immediate arrest or legal action.
Police also cautioned against involvement in illegal telecom equipment setups such as SIM boxes, which are banned under Indian telecom regulations. Participation—knowingly or unknowingly—in such operations can result in criminal charges under the Indian Telegraph Act, IT Act, and IPC provisions.
The article was published by The 420 with contributions from State Cyber Police, Rushi Mehta, Senior Consultant to I4C, MHA and resources from DoT.