The ratings of five communications equipment stocks are down this week, according to the Portfolio Grader database. Each of these rates a “D” (“sell”) or “F” overall (“strong sell”).

This week, ARRIS Group, Inc. (ARRS) falls to a D (“sell”), worse than last week’s grade of C (“hold”). ARRIS is a global communications technology company specializing in the design and engineering of broadband network solutions. For more information, get Portfolio Grader’s complete analysis of ARRS stock.

Applied Optoelectronics, Inc.’s (AAOI) rating falls this week to an F (“strong sell”), down from last week’s C (“sell”). The stock gets F’s in Earnings Surprise and Cash Flow. As of May 14, 2015, 12.6% of outstanding Applied Optoelectronics, Inc. shares were held short. The trailing PE Ratio for the stock is 67.30. To get an in-depth look at AAOI, get Portfolio Grader’s complete analysis of AAOI stock.

This week, Dragonwave Inc. (DRWI) drops from a C to a D rating. DragonWave is a producer of high-capacity packet microwave solutions which support networking and other data transmission needs. The stock gets F’s in Equity and Cash Flow. Trade volume is up 1112.8% from the previous week. For more information, get Portfolio Grader’s complete analysis of DRWI stock.

Clearfield, Inc. (CLFD) experiences a ratings drop this week, going from last week’s D to an F. Clearfield offers telecommunications equipment and products in the United States. The stock gets F’s in Earnings Growth, Earnings Momentum and Sales Growth. As of May 14, 2015, 10.2% of outstanding Clearfield, Inc. shares were held short. The stock has a trailing PE Ratio of 51.10. To get an in-depth look at CLFD, get Portfolio Grader’s complete analysis of CLFD stock.

This week, Sonus Networks, Inc.’s (SONS) rating worsens to a D from the company’s C rating a week ago. Sonus Networks provides voice infrastructure solutions for wireline and wireless service providers. For more information, get Portfolio Grader’s complete analysis of SONS 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.