Soul Communications has been found to have breached the Telecommunications Act in a 2008 incident, during which emergency services could not confirm the location of a caller reporting a fatal home invasion in Sydney.
The telco admitted it failed to provide some of the information it is required by law to supply to the Integrated Public Number Database (IPND).
The IPND is a database of public numbers managed by Telstra as a condition of its carrier licence.
According to the communications watchdog, the IPND is the "key data source for emergency service organisations responding to emergency calls, including those from mobile phones, when the caller details and/or the location of the incident need to be confirmed.
"The information provided by Soul to the IPND Manager in this circumstance did not include the unit number of the service address, in part as a result of the fact that the block and unit information was not recognised by Soul's third party validation tool," ACMA said.
"The provision of accurate information to the IPND Manager is critically important," said ACMA chairman, Chris Chapman.
"The lack of accurate information can result in delays in addressing emergency calls or even an inability to respond at all to time-critical emergency situations."
Soul had since committed to an enforceable undertaking [PDF] following an ACMA investigation into the incident.
The telco had "upgraded its data-checking processes and undertook a full data audit to check its IPND records" and cooperated fully with the investigation, ACMA said.