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

Black Box‘s (NASDAQ:BBOX) rating falls to a D (“sell”) this week, down from C (“hold”) the week prior. Black Box is a network infrastructure services provider that offers one-source network infrastructure services for communications systems. In Portfolio Grader’s specific subcategories of Earnings Surprise, Cash Flow, and Margin Growth, BBOX also gets an F. For a full analysis of BBOX stock, visit Portfolio Grader.

ShoreTel‘s (NASDAQ:SHOR) rating falls this week to an F (“strong sell”), down from last week’s D (“sell”). ShoreTel is a provider of Internet Protocol, or IP, unified communications systems for enterprises. The stock gets F’s in Earnings Revisions and Equity. To get an in-depth look at SHOR, get Portfolio Grader’s complete analysis of SHOR stock.

Slipping from a C to a D rating, Globecomm Systems (NASDAQ:GCOM) takes a hit this week. Globecomm Systems provides end-to-end, value-added satellite-based communications solutions. The stock also gets an F in Earnings Surprise. For more information, get Portfolio Grader’s complete analysis of GCOM stock.

UTStarcom Holdings (NASDAQ:UTSI) experiences a ratings drop this week, going from last week’s C to a D. UTStarcom Holdings provides communications equipment for service providers that operate wireless and wireline networks. For a full analysis of UTSI stock, visit Portfolio Grader.

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.