EXHIBIT 24
POWER OF ATTORNEY
Know all by these presents, that the undersigned hereby constitutes and appoints
Justin Ferguson the undersigned's true and lawful attorney-in-fact to:
(1) prepare, execute in the undersigned's name and on the undersigned's behalf, and
submit to the U.S. Securities and Exchange Commission (the "SEC") a Form ID, including
amendments thereto, and any other documents necessary or appropriate to obtain codes and
passwords enabling the undersigned to make electronic filings with the SEC of reports
required by Section 16(a) of the Securities Exchange Act of 1934 (the "Act") or any rule
or regulation of the SEC;
(2) execute for and on behalf of the undersigned, in the undersigned's capacity as an
officer and/or director of Ribbon Communications Inc. (the "Company"), Forms 3, 4, and 5
in accordance with Section 16(a) of the Act and the rules thereunder, and any other forms
or reports the undersigned may be required to file in connection with the undersigned's
ownership, acquisition, or disposition of securities of the Company;
(3) do and perform any and all acts for and on behalf of the undersigned which may be
necessary or desirable to complete and execute any such Form 3, 4, or 5, or other form
or report, and timely file such form or report with the SEC and any stock exchange or
similar authority; and
(4) take any other action of any type whatsoever in connection with the foregoing which,
in the opinion of such attorney-in-fact, may be of benefit to, in the best interest of, or
legally required by, the undersigned, it being understood that the documents executed by
such attorney-in-fact on behalf of the undersigned pursuant to this Power of Attorney
shall be in such form and shall contain such terms and conditions as such attorney-in-
fact may approve in such attorney-in-fact's discretion.
The undersigned hereby grants to such attorney-in-fact full power and authority to do
and perform any and every act and thing whatsoever requisite, necessary, or proper to be done
in the exercise of any of the rights and powers herein granted, as fully to all intents and
purposes as the undersigned might or could do if personally present, with full power of
substitution or revocation, hereby ratifying and confirming all that such attorney-in-fact, or
such attorney-in-fact's substitute or substitutes, shall lawfully do or cause to be done by
virtue of this power of attorney and the rights and powers herein granted. The undersigned
acknowledges that the foregoing attorney-in-fact, in serving in such capacity at the request of
the undersigned, is not assuming, nor is the Company assuming, any of the undersigned's respons-
ibilities to comply with Section 16 of the Act. This Power of Attorney shall remain in full force
and effect until the undersigned is no longer required to file Forms 3, 4, and 5 with respect to
the undersigned's holdings of and transactions in securities issued by the Company, unless earlier
revoked by the undersigned in a signed writing delivered to the foregoing attorneys-in-fact.
IN WITNESS WHEREOF, the undersigned has caused this Power of Attorney to be
executed as of this 18th day of May, 2020.
/s/ Eric Marmurek
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Eric Marmurek