The southward trend in estimate revisions is probably the most talked-about issue right now. As more and more companies come up with their quarterly results, market consensus of negative earnings growth for the fourth consecutive quarter is looking more likely. This view is further solidified by the magnitude of downward revisions for the quarter, which is the highest in recent past. The S&P 500 earnings forecast for this quarter against the year-ago period indicates a 10.9% decline as per the Zacks Trend report.However, the U.S. telecommunications industry is looking up in spite of estimates falling over the last three months. In fact, telecommunications is one of the few industries to have undergone rapid technological improvement even amid the recession. Although the U.S. telecom industry has lately emerged as an intensely contested space where cut-throat pricing competition may put pressure on margins going forward, rising demand for technologically superior products provides a silver lining in an otherwise tough environment.Moreover, the fibre optic network, one of the biggest advancement in telecom technologies as of today, is increasingly becoming the most sought-after technology for secure and fast data transmission over long distances. Going forward, the wireline industry will largely evolve around the fibre-based superfast gigabit data transmission network, enabling telecom operators and equipment manufacturers to adopt newer business models in order to boost revenues.Let’s have a look at the major telecom companies that are about to release their results early next week.T-Mobile US, Inc. TMUS is slated to release first-quarter 2016 results on Apr 27, before market opens. Last quarter, T-Mobile US delivered a positive earnings surprise of 183.33%. We believe that the addition of Youtube in its ‘Binge On’ service will allow it to expand its customer base. Also, industry data show that T-Mobile has been broadening its subscriber base more rapidly than its rivals, while maintaining its existing subscriber base.For this quarter, T-Mobile US has an Earnings ESP of -23.53%. This is because the Most Accurate estimate stands at 13 cents while the Zacks Consensus Estimate is pegged higher at 17 cents. (Read more: What Awaits T-Mobile US (TMUS) This Earnings Season?)We expect U.S. telecom behemoth AT&T, Inc. T to beat expectations when it reports first-quarter 2016 numbers on Apr 26, after the market closes. Last quarter, AT&T recorded a 1.56% negative earnings surprise. The re-launch of the unlimited wireless data plan by AT&T is likely to boost sales as unlimited data is a huge selling point for customers who are weary of data caps and look for unrestricted access to high-definition video. Meanwhile, expansion in the fiber arena and efforts to enhance its broadband services should result in high profit accretion for the wireline business.For this quarter, the Earnings ESP for AT&T stands at +1.45% because the Most Accurate estimate stands at 70 cents while the Zacks Consensus Estimate is pegged at 69 cents. The company has a Zacks Rank #3 (Hold), which when combined with its positive ESP, makes us reasonably confident of an earnings beat. (Read more: AT&T (T) to Report Q1 Earnings: A Beat in the Cards?)Leading optical transport network developer, Infinera Corporation INFN is slated to release first-quarter 2016 results on Apr 27, after the market closes. Introduction of the innovative Infinite Capacity Engine, a multi-terabit optical subsystem that facilitates a step function in optical wave division multiplexing (WDM) performance, is a huge positive for the company. Also, increased deployment of Infinera Cloud Xpress with 100-gigabit Ethernet (GbE) for accelerated datacenter interconnection bodes well.For this quarter, Infinera has an Earnings ESP of 0.00%. This is because both the Most Accurate estimate and the Zacks Consensus Estimate of this Zacks Rank #3 stock are pegged at 11 cents. (Read more: Infinera (INFN) Q1 Earnings: Surprise in Store for the Stock?)Stay tuned! Check later on our full write-up on earnings releases of these stocks.Want the latest recommendations from Zacks Investment Research? Today, you can download 7 Best Stocks for the Next 30 Days. Click to get this free report >>Want the latest recommendations from Zacks Investment Research? Today, you can download 7 Best Stocks for the Next 30 Days. Click to get this free report INFINERA CORP (INFN): Free Stock Analysis Report AT&T INC (T): Free Stock Analysis Report T-MOBILE US INC (TMUS): Free Stock Analysis Report To read this article on Zacks.com click here. Zacks Investment Research