Demand for communications infrastructure is slowing and price is becoming more aggressive, Cowen’s John Anthony asserts in a research report this morning. Anthony says he now sees no growth in global aggregate capital spending budgets for the sector in 2008 versus 2007. He says a zero growth scenario affects a broad range of companies, but in particular worries about Tellabs (TLAB), Adtran (ADTN) and Bookham (BKHM), and today lowered his ratings on all three to Neutral from Outperform; he also trimmed earnings estimates for the companies.

Anthony writes that “evidence points to a continued weakening of end-demand.” He also says that “evidence from multiple points within the communications supply chain indicates that ASPs in most product categories have come under a significant amount of pressure over the past few months.” He thinks the earnings outlook for some companies in the sector “are in jeopardy.”

In today’s trading, Tellabs is down 31 cents, or 2.8%, to $10.66; Adtran is off 4 cents to $25.95 and Bookhan is down 5 cents to $2.03.

Earlier: Tellabs: Goldman Cuts Rating to Sell On Relative Valuation Basis