Telstra ((TLS)) has raised the competition heat in the telecommunications sector with its purchase of Adelaide-based ISP Adam Internet, for an undisclosed sum. While only a small acquisition for the giant of the sector, it will make players in the middle tier of the broadband marketplace sit up and take notice, according to brokers. Most see it, with Telstra's stated aim to run Adam as a separate entity, as a bid to challenge Optus ((SGT)),