001 - Document - Document and Entity Information link:presentationLink link:definitionLink link:calculationLink 002 - Statement - CONSOLIDATED BALANCE SHEETS (unaudited) link:presentationLink link:definitionLink link:calculationLink 003 - Statement - CONSOLIDATED BALANCE SHEETS (unaudited) (Parentheticals) link:presentationLink link:definitionLink link:calculationLink 004 - Statement - CONSOLIDATED STATEMENTS OF COMPREHENSIVE INCOME (unaudited) link:presentationLink link:definitionLink link:calculationLink 005 - Statement - CONSOLIDATED STATEMENTS OF COMPREHENSIVE INCOME (unaudited) (Parentheticals) link:presentationLink link:definitionLink link:calculationLink 006 - Statement - CONSOLIDATED STATEMENTS OF CASH FLOWS (unaudited) link:presentationLink link:definitionLink link:calculationLink 007 - Disclosure - Basis of Presentation link:presentationLink link:definitionLink link:calculationLink 008 - Disclosure - Fair Value Measurements link:presentationLink link:definitionLink link:calculationLink 009 - Disclosure - Inventories link:presentationLink link:definitionLink link:calculationLink 010 - Disclosure - Computation of Earnings per Share link:presentationLink link:definitionLink link:calculationLink 011 - Disclosure - Stock-Based Compensation link:presentationLink link:definitionLink link:calculationLink 012 - Disclosure - Business Segments link:presentationLink link:definitionLink link:calculationLink 013 - Disclosure - Statement of Stockholders' Equity link:presentationLink link:definitionLink link:calculationLink 014 - Disclosure - Recent Accounting Pronouncements link:presentationLink link:definitionLink link:calculationLink 015 - Disclosure - Sale of Patent Assets link:presentationLink link:definitionLink link:calculationLink 016 - Disclosure - Income Taxes link:presentationLink link:definitionLink link:calculationLink 017 - Disclosure - Dividends link:presentationLink link:definitionLink link:calculationLink 018 - Disclosure - Variable Interest Entity link:presentationLink link:definitionLink link:calculationLink 019 - Disclosure - DSL Service Assurance Hardware Exit link:presentationLink link:definitionLink link:calculationLink 020 - Disclosure - Inventories (Tables) link:presentationLink link:definitionLink link:calculationLink 021 - Disclosure - Computation of Earnings per Share (Tables) link:presentationLink link:definitionLink link:calculationLink 022 - Disclosure - Stock-Based Compensation (Tables) link:presentationLink link:definitionLink link:calculationLink 023 - Disclosure - Business Segments (Tables) link:presentationLink link:definitionLink link:calculationLink 024 - Disclosure - Statement of Stockholders' Equity (Tables) link:presentationLink link:definitionLink link:calculationLink 025 - Disclosure - DSL Service Assurance Hardware Exit (Tables) link:presentationLink link:definitionLink link:calculationLink 026 - Disclosure - Fair Value Measurements (Details Textuals) link:presentationLink link:definitionLink link:calculationLink 027 - Disclosure - Inventories (Details) link:presentationLink link:definitionLink link:calculationLink 028 - Disclosure - Computation of Earnings per Share (Details) link:presentationLink link:definitionLink link:calculationLink 029 - Disclosure - Computation of Earnings per Share (Details Textuals) link:presentationLink link:definitionLink link:calculationLink 030 - Disclosure - Stock-Based Compensation (Details) link:presentationLink link:definitionLink link:calculationLink 031 - Disclosure - Stock-Based Compensation (Details Textuals) link:presentationLink link:definitionLink link:calculationLink 032 - Disclosure - Business Segment - Results of operations for reportable segments (Details) link:presentationLink link:definitionLink link:calculationLink 033 - Disclosure - Business Segments - Revenues were generated from following geographic regions (Details 1) link:presentationLink link:definitionLink link:calculationLink 034 - Disclosure - Business Segments (Details Textuals) link:presentationLink link:definitionLink link:calculationLink 035 - Statement - Statement of Stockholders' Equity (Details) link:presentationLink link:definitionLink link:calculationLink 036 - Disclosure - Sale of Patent Assets (Detail Textuals) link:presentationLink link:definitionLink link:calculationLink 037 - Disclosure - Income Taxes (Details Textuals) link:presentationLink link:definitionLink link:calculationLink 039 - Disclosure - Variable Interest Entity (Details Textuals) link:presentationLink link:definitionLink link:calculationLink 040 - Disclosure - DSL Service Assurance Hardware Exit - Exit cost activities (Details ) link:presentationLink link:definitionLink link:calculationLink 041 - Disclosure - DSL Service Assurance Hardware Exit (Details Textuals) link:presentationLink link:definitionLink link:calculationLink 038 - Disclosure - Dividends (Detail Textuals) link:presentationLink link:definitionLink link:calculationLink