<?xml version="1.0" encoding="utf-8"?>
<ownershipDocument>
    <schemaVersion>X0201</schemaVersion>

    <documentType>4</documentType>
  <periodOfReport>2003-11-03</periodOfReport>
  <notSubjectToSection16>1</notSubjectToSection16>
    <issuer>
        <issuerCik>0001095594</issuerCik>
        <issuerName>T/R SYSTEMS INC</issuerName>
        <issuerTradingSymbol>TRSI</issuerTradingSymbol>
  </issuer>
  <reportingOwner>
        <reportingOwnerId>
            <rptOwnerCik>0000879427</rptOwnerCik>
            <rptOwnerName>SEVIN ROSEN FUND IV LP</rptOwnerName>
        </reportingOwnerId>
        <reportingOwnerAddress>
            <rptOwnerStreet1>13455 NOEL ROAD</rptOwnerStreet1>
            <rptOwnerStreet2>SUITE 1670</rptOwnerStreet2>
            <rptOwnerCity>DALLAS</rptOwnerCity>
            <rptOwnerState>TX</rptOwnerState>
            <rptOwnerZipCode>75240</rptOwnerZipCode>
            <rptOwnerStateDescription></rptOwnerStateDescription>
        </reportingOwnerAddress>
            <reportingOwnerRelationship>
      <isDirector>0</isDirector>
      <isOfficer>0</isOfficer>
      <isTenPercentOwner>1</isTenPercentOwner>
      <isOther>0</isOther>
    </reportingOwnerRelationship>
  </reportingOwner>
  <nonDerivativeTable>
    <nonDerivativeTransaction>
      <securityTitle>
        <value>Common Stock</value>
      </securityTitle>
      <transactionDate>
        <value>2003-11-03</value>
      </transactionDate>
      <transactionCoding>
        <transactionFormType>4</transactionFormType>
        <transactionCode>D</transactionCode>
        <equitySwapInvolved>0</equitySwapInvolved>
        <footnoteId id="F1"/>
      </transactionCoding>
      <transactionTimeliness>
        <value></value>
      </transactionTimeliness>
      <transactionAmounts>
        <transactionShares>
          <value>1548350</value>
        </transactionShares>
        <transactionPricePerShare>
          <value>1.5748</value>
        </transactionPricePerShare>
        <transactionAcquiredDisposedCode>
          <value>D</value>
        </transactionAcquiredDisposedCode>
      </transactionAmounts>
      <postTransactionAmounts>
        <sharesOwnedFollowingTransaction>
          <value>0</value>
        </sharesOwnedFollowingTransaction>
      </postTransactionAmounts>
      <ownershipNature>
        <directOrIndirectOwnership>
          <value>D</value>
        </directOrIndirectOwnership>
      </ownershipNature>
    </nonDerivativeTransaction>
  </nonDerivativeTable>
  <footnotes>
    <footnote id="F1">On 11/3/2003, T/R Systems, Inc. merged with a subsidiary of Electronics For Imaging, Inc.  As a result of the merger each common share of T/R Systems, Inc. was cancelled and converted into the right to recieve a cash payment of $1.5748 per share.</footnote>
  </footnotes>
  <ownerSignature>
    <signatureName>John V. Jaggers, Attorney-In-Fact</signatureName>
    <signatureDate>2003-11-12</signatureDate>
  </ownerSignature>
</ownershipDocument>

