Given the ease of submitting resumes to job sites, Linked-In, recruiters et al, one can imagine the avalanche of documents that employers receive for each of their job postings. Those resumes that survive the automated word-screening are sent to HR or a Talent Acquisition type for human assessment. A phone screenings is likely your first opportunity to speak to a real someone about your suitability for the posting.
Please note that phone screenings are intended to weed-out the unqualified of which there are many from the Talent Acquisition Rep's perspective. Once that you get past the phone screening then you are in the queue to speak with someone who knows something about the posted position and is likely able to discuss the details of the role and its requirements.
In short, Phone Screenings are Screening-Out Processes not Screening-In Processes. My distinction may be subtle and it is important, please.
So, keep your phone-screen as brief as possible while being as cooperative and professional as possible. Do not volunteer information; do not tty to wow the recruiter conducting the call as they are likely using a checklist-to assess your aptitude for being moved along in the process. The recruiter has many screenings to conduct, so keep it friendly, confident and to the point.
Here is a typical note that you will receive re a Phone Screen. This one from a large entity in the RTP who is inclined to hire vets.
"This email is to confirm your phone interview for Business System Analyst / IT Project Manager role with Joe Gish, Lead Talent Acquisition Partner. The phone call will take place on Wednesday, October 17, 2018 at 10:00 am EST. Gish will call you at the number provided on your resume. Please review our website as well as the job description so you can clearly communicate how your experience relates to what we are looking for and be sure to prepare thoughtful questions. If you have any questions before your phone interview, please let me know."
Please note that preparation is important. The Recruiter will be impressed if you demonstrate that you've taken their, the company's, point of view about your possible suitability for the open position. Most applicants do not prepare properly and only stand-by to answer questions. Or worse, they only show keen interest in what the job pays and how many days of paid vacation are offered.
Finally, companies seek talent. Hiring is a complicated and often risky process to them. Make it easy on the recruiter by doing your homework, being polite and precise on the call and respectful of the time and mission of the recruiter.