<SEC-DOCUMENT>0001615594-18-000012.txt : 20180215
<SEC-HEADER>0001615594-18-000012.hdr.sgml : 20180215
<ACCEPTANCE-DATETIME>20180215100007
ACCESSION NUMBER:		0001615594-18-000012
CONFORMED SUBMISSION TYPE:	4
PUBLIC DOCUMENT COUNT:		1
CONFORMED PERIOD OF REPORT:	20180102
FILED AS OF DATE:		20180215
DATE AS OF CHANGE:		20180215

REPORTING-OWNER:	

	OWNER DATA:	
		COMPANY CONFORMED NAME:			Lacey Roger HD
		CENTRAL INDEX KEY:			0001469238

	FILING VALUES:
		FORM TYPE:		4
		SEC ACT:		1934 Act
		SEC FILE NUMBER:	001-31588
		FILM NUMBER:		18616465

	MAIL ADDRESS:	
		STREET 1:		10900 RED CIRCLE DRIVE
		CITY:			MINNETONKA
		STATE:			MN
		ZIP:			55343

ISSUER:		

	COMPANY DATA:	
		COMPANY CONFORMED NAME:			COMMUNICATIONS SYSTEMS INC
		CENTRAL INDEX KEY:			0000022701
		STANDARD INDUSTRIAL CLASSIFICATION:	TELEPHONE & TELEGRAPH APPARATUS [3661]
		IRS NUMBER:				410957999
		STATE OF INCORPORATION:			MN
		FISCAL YEAR END:			1231

	BUSINESS ADDRESS:	
		STREET 1:		10900 RED CIRCLE DRIVE
		CITY:			MINNETONKA
		STATE:			MN
		ZIP:			55343
		BUSINESS PHONE:		9529961674

	MAIL ADDRESS:	
		STREET 1:		10900 RED CIRCLE DRIVE
		CITY:			MINNETONKA
		STATE:			MN
		ZIP:			55343
</SEC-HEADER>
<DOCUMENT>
<TYPE>4
<SEQUENCE>1
<FILENAME>primary_doc.xml
<DESCRIPTION>PRIMARY DOCUMENT
<TEXT>
<XML>
<?xml version="1.0"?>
<ownershipDocument>

    <schemaVersion>X0306</schemaVersion>

    <documentType>4</documentType>

    <periodOfReport>2018-01-02</periodOfReport>

    <notSubjectToSection16>0</notSubjectToSection16>

    <issuer>
        <issuerCik>0000022701</issuerCik>
        <issuerName>COMMUNICATIONS SYSTEMS INC</issuerName>
        <issuerTradingSymbol>JCS</issuerTradingSymbol>
    </issuer>

    <reportingOwner>
        <reportingOwnerId>
            <rptOwnerCik>0001469238</rptOwnerCik>
            <rptOwnerName>Lacey Roger HD</rptOwnerName>
        </reportingOwnerId>
        <reportingOwnerAddress>
            <rptOwnerStreet1>10900 RED CIRCLE DRIVE</rptOwnerStreet1>
            <rptOwnerStreet2></rptOwnerStreet2>
            <rptOwnerCity>MINNETONKA</rptOwnerCity>
            <rptOwnerState>MN</rptOwnerState>
            <rptOwnerZipCode>55343</rptOwnerZipCode>
            <rptOwnerStateDescription></rptOwnerStateDescription>
        </reportingOwnerAddress>
        <reportingOwnerRelationship>
            <isDirector>1</isDirector>
            <isOfficer>0</isOfficer>
            <isTenPercentOwner>0</isTenPercentOwner>
            <isOther>0</isOther>
        </reportingOwnerRelationship>
    </reportingOwner>

    <nonDerivativeTable>
        <nonDerivativeTransaction>
            <securityTitle>
                <value>Common Stock</value>
            </securityTitle>
            <transactionDate>
                <value>2018-01-02</value>
            </transactionDate>
            <transactionCoding>
                <transactionFormType>4</transactionFormType>
                <transactionCode>A</transactionCode>
                <equitySwapInvolved>0</equitySwapInvolved>
            </transactionCoding>
            <transactionTimeliness>
                <value></value>
            </transactionTimeliness>
            <transactionAmounts>
                <transactionShares>
                    <value>160.406</value>
                </transactionShares>
                <transactionPricePerShare>
                    <value>3.8</value>
                </transactionPricePerShare>
                <transactionAcquiredDisposedCode>
                    <value>A</value>
                </transactionAcquiredDisposedCode>
            </transactionAmounts>
            <postTransactionAmounts>
                <sharesOwnedFollowingTransaction>
                    <value>54101.858</value>
                    <footnoteId id="F1"/>
                </sharesOwnedFollowingTransaction>
            </postTransactionAmounts>
            <ownershipNature>
                <directOrIndirectOwnership>
                    <value>D</value>
                </directOrIndirectOwnership>
            </ownershipNature>
        </nonDerivativeTransaction>
    </nonDerivativeTable>

    <footnotes>
        <footnote id="F1">Shares purchased through broker-sponsored Dividend Reinvestment Plan.</footnote>
    </footnotes>

    <ownerSignature>
        <signatureName>Suzette McNally, Attorney-in-Fact for Roger HD Lacey</signatureName>
        <signatureDate>2018-02-15</signatureDate>
    </ownerSignature>
</ownershipDocument>
</XML>
</TEXT>
</DOCUMENT>
</SEC-DOCUMENT>
