This week, the overall grades of three Communications Equipment stocks are lower, according to the Portfolio Grader database. Each of these rates a “D” (“sell”) or “F” overall (“strong sell”).

Sonus Networks‘ (NASDAQ:SONS) rating falls this week to a F (“strong sell”), down from last week’s D (“sell”). Sonus Networks provides voice infrastructure solutions for wireline and wireless service providers. In Portfolio Grader’s specific subcategory of Earnings Revisions, SONS also gets an F. To get an in-depth look at SONS, get Portfolio Grader’s complete analysis of SONS stock.

This week, UTStarcom Holdings (NASDAQ:UTSI) falls to a D (“sell”), worse than last week’s grade of C (“hold”). UTStarcom Holdings provides communications equipment for service providers that operate wireless and wireline networks. The stock has a trailing PE Ratio of 25.50. For more information, get Portfolio Grader’s complete analysis of UTSI stock.

AudioCodes (NASDAQ:AUDC) experiences a ratings drop this week, going from last week’s D to a F. AudioCodes designs, develops, and markets products for voice and data over packet networks. The stock receives F’s in Earnings Growth, Earnings Revisions, and Equity. Margin Growth and Sales Growth also get F’s. To get an in-depth look at AUDC, get Portfolio Grader’s complete analysis of AUDC stock.

Louis Navellier’s proprietary Portfolio Grader stock ranking system assesses roughly 5,000 companies every week based on a number of fundamental and quantitative measures. Stocks are given a letter grade based on their results — with A being “strong buy,” and F being “strong sell.” Explore the tool here.