Telstra has identified a significant issue affecting some Samsung mobile phone users, which may prevent them from making emergency calls to triple-0. Testing revealed that over 70 Samsung models are not connecting properly, with 11 older Galaxy models requiring replacement and about 60 others needing software updates.

Telstra announced that customers with the older models must replace their devices within 28 days of notification to avoid being blocked from the network. The company stated, "Under the government's Emergency Service Call Determination, all mobile network operators are required to block devices from their networks that are not configured to access emergency call services."

The affected models include popular devices such as the Galaxy Note 5 and Galaxy S7. Telstra's testing indicated that these phones fail to connect to the Vodafone network when both the Telstra and Optus networks are unavailable. The company explained that for Telstra customers, the primary network is Telstra, with Optus or Vodafone as alternatives.

In light of recent outages, Optus customers have also reported issues with triple-0 calls failing. The company has acknowledged the problem and is contacting affected users. Similar to Telstra, Optus will block devices that are not replaced within 28 days of notification.

During network outages, mobile phones are expected to utilize a "camp on" system to connect to the next available network. However, Telstra indicated that this system is not functioning as intended. Carol Bennett, CEO of the Australian Communications Consumer Action Network (ACCAN), estimated that the issue could impact over 100,000 customers, with approximately 50,000 from Telstra and another 50,000 from Optus.

This situation has raised concerns about the reliability of Australia's emergency services, particularly following two significant outages experienced by Optus. The largest outage in September has been linked to three fatalities, as hundreds of customers were unable to make emergency calls, leading to investigations into the telco's compliance with legal obligations.

The Australian Communications and Media Authority, along with Vodafone's owner TPG, Telstra, and Optus, have been contacted for further comments regarding this ongoing issue. The list of devices that need to be replaced includes: - SM-N920I Galaxy Note 5 - SM-J530Y Galaxy J5 (2017) - SM-J320ZN Galaxy J3 (2016) - SM-J120ZN Galaxy J1 (2016) - SM-G935F Galaxy S7 Edge - SM-G930F Galaxy S7 - SM-G928I Galaxy S6 Edge+ - SM-G925I Galaxy S6 Edge - SM-G920I Galaxy S6 - SM-A720F Galaxy A7 (2017) - SM-A520F Galaxy A5 (2017)