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

ARRIS Group, Inc.’s (ARRS) rating falls to a D (“sell”) this week, down from C (“hold”) the week prior. ARRIS is a global communications technology company specializing in the design and engineering of broadband network solutions. Shares of the stock have been exchanging at an usually rapid pace, twice the rate of the week prior. 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 June 4, 2015, 12.9% of outstanding Applied Optoelectronics, Inc. shares were held short. The trailing PE Ratio for the stock is 81.20. To get an in-depth look at AAOI, get Portfolio Grader’s complete analysis of AAOI stock.

The rating of Dragonwave Inc. (DRWI) slips from a C to a D. 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. Shares of the stock have been trading at an exceptionally rapid pace, up twofold from the week prior. For more information, get Portfolio Grader’s complete analysis of DRWI stock.

Clearfield, Inc. (CLFD) earns an F this week, falling from last week’s grade of D. 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 June 4, 2015, 11.1% of outstanding Clearfield, Inc. shares were held short. The stock currently has a trailing PE Ratio of 58.70. To get an in-depth look at CLFD, get Portfolio Grader’s complete analysis of CLFD stock.

Slipping from a C to a D rating, Sonus Networks, Inc. (SONS) takes a hit this week. 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.