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  <xsd:element id="sncr_NumberOfVotesPerShare" name="NumberOfVotesPerShare" nillable="true" substitutionGroup="xbrli:item" type="xbrli:integerItemType" xbrli:periodType="duration" />
  <xsd:element id="sncr_NumberofElectedDirectors" name="NumberofElectedDirectors" nillable="true" substitutionGroup="xbrli:item" type="xbrli:integerItemType" xbrli:periodType="instant" />
  <xsd:element abstract="true" id="sncr_OpenExchangeSettlementMember" name="OpenExchangeSettlementMember" nillable="true" substitutionGroup="xbrli:item" type="nonnum:domainItemType" xbrli:periodType="duration" />
  <xsd:element id="sncr_OtherComprehensiveIncomeNetGainLossOnIntraEntityForeignCurrencyTransactionsArisingDuringPeriodNetOfTax" name="OtherComprehensiveIncomeNetGainLossOnIntraEntityForeignCurrencyTransactionsArisingDuringPeriodNetOfTax" nillable="true" substitutionGroup="xbrli:item" type="xbrli:monetaryItemType" xbrli:balance="credit" xbrli:periodType="duration" />
  <xsd:element id="sncr_OtherSundryNonoperatingIncomeExpenseNet" name="OtherSundryNonoperatingIncomeExpenseNet" nillable="true" substitutionGroup="xbrli:item" type="xbrli:monetaryItemType" xbrli:balance="credit" xbrli:periodType="duration" />
  <xsd:element abstract="true" id="sncr_OwnershipPercentageAxis" name="OwnershipPercentageAxis" nillable="true" substitutionGroup="xbrldt:dimensionItem" type="xbrli:stringItemType" xbrli:periodType="duration" />
  <xsd:element abstract="true" id="sncr_OwnershipPercentageDomain" name="OwnershipPercentageDomain" nillable="true" substitutionGroup="xbrli:item" type="nonnum:domainItemType" xbrli:periodType="duration" />
  <xsd:element id="sncr_PaidinKindInterestIncome" name="PaidinKindInterestIncome" nillable="true" substitutionGroup="xbrli:item" type="xbrli:monetaryItemType" xbrli:balance="credit" xbrli:periodType="duration" />
  <xsd:element id="sncr_PreferredStockOwnershipPercentage" name="PreferredStockOwnershipPercentage" nillable="true" substitutionGroup="xbrli:item" type="num:percentItemType" xbrli:periodType="duration" />
  <xsd:element id="sncr_ProceedsFromPreviousDisposition" name="ProceedsFromPreviousDisposition" nillable="true" substitutionGroup="xbrli:item" type="xbrli:monetaryItemType" xbrli:balance="debit" xbrli:periodType="duration" />
  <xsd:element abstract="true" id="sncr_ProfessionalServicesMember" name="ProfessionalServicesMember" nillable="true" substitutionGroup="xbrli:item" type="nonnum:domainItemType" xbrli:periodType="duration" />
  <xsd:element id="sncr_RedeemableNoncontrollingInterestMember" name="RedeemableNoncontrollingInterestMember" nillable="true" substitutionGroup="xbrli:item" type="nonnum:domainItemType" xbrli:periodType="duration" />
  <xsd:element id="sncr_RevenueRemainingPerformanceObligationExpectedTimingofSatisfactionPercent" name="RevenueRemainingPerformanceObligationExpectedTimingofSatisfactionPercent" nillable="true" substitutionGroup="xbrli:item" type="num:percentItemType" xbrli:periodType="duration" />
  <xsd:element abstract="true" id="sncr_STIHMember" name="STIHMember" nillable="true" substitutionGroup="xbrli:item" type="nonnum:domainItemType" xbrli:periodType="duration" />
  <xsd:element abstract="true" id="sncr_STIMember" name="STIMember" nillable="true" substitutionGroup="xbrli:item" type="nonnum:domainItemType" xbrli:periodType="duration" />
  <xsd:element abstract="true" id="sncr_SequentialTechnologyInternationalHoldingsLLCMember" name="SequentialTechnologyInternationalHoldingsLLCMember" nillable="true" substitutionGroup="xbrli:item" type="nonnum:domainItemType" xbrli:periodType="duration" />
  <xsd:element abstract="true" id="sncr_SequentialTechnologyInternationalLLCMember" name="SequentialTechnologyInternationalLLCMember" nillable="true" substitutionGroup="xbrli:item" type="nonnum:domainItemType" xbrli:periodType="duration" />
  <xsd:element abstract="true" id="sncr_ShareBasedCompensationArrangementByShareBasedPaymentAwardAggregateIntrinsicValueAbstract" name="ShareBasedCompensationArrangementByShareBasedPaymentAwardAggregateIntrinsicValueAbstract" nillable="true" substitutionGroup="xbrli:item" type="xbrli:stringItemType" xbrli:periodType="duration" />
  <xsd:element abstract="true" id="sncr_ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsWeightedAverageRemainingContractualTermAbstract" name="ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsWeightedAverageRemainingContractualTermAbstract" nillable="true" substitutionGroup="xbrli:item" type="xbrli:stringItemType" xbrli:periodType="duration" />
  <xsd:element id="sncr_ShareRepurchaseProgram2016Member" name="ShareRepurchaseProgram2016Member" nillable="true" substitutionGroup="xbrli:item" type="nonnum:domainItemType" xbrli:periodType="duration" />
  <xsd:element abstract="true" id="sncr_SilverPrivateHoldingsILLCMember" name="SilverPrivateHoldingsILLCMember" nillable="true" substitutionGroup="xbrli:item" type="nonnum:domainItemType" xbrli:periodType="duration" />
  <xsd:element abstract="true" id="sncr_SubscriptionServicesMember" name="SubscriptionServicesMember" nillable="true" substitutionGroup="xbrli:item" type="nonnum:domainItemType" xbrli:periodType="duration" />
  <xsd:element abstract="true" id="sncr_TenPercentorGreaterOwnershipMember" name="TenPercentorGreaterOwnershipMember" nillable="true" substitutionGroup="xbrli:item" type="nonnum:domainItemType" xbrli:periodType="duration" />
  <xsd:element abstract="true" id="sncr_TheSecuritiesLawActionsMember" name="TheSecuritiesLawActionsMember" nillable="true" substitutionGroup="xbrli:item" type="nonnum:domainItemType" xbrli:periodType="duration" />
  <xsd:element abstract="true" id="sncr_TransactionServicesMember" name="TransactionServicesMember" nillable="true" substitutionGroup="xbrli:item" type="nonnum:domainItemType" xbrli:periodType="duration" />
</xsd:schema>
