As enhanced 9-1-1 service becomes available, each telephone company shall convert, in accordance with an electronic switching systems modernization schedule submitted to and approved by the Public Utilities Regulatory Authority, each coin telephone within areas served by such enhanced 9-1-1 service to dial tone first capability, which shall allow a caller to dial 9-1-1 without first inserting a coin or paying any other charge. Each telephone company shall prominently display instructions on how to access the enhanced 9-1-1 system on those coin telephones which have been converted to dial tone first capability.