Note 5 - Revenue (Details) - USD ($)	3 Months Ended
	Mar. 31, 2019	Mar. 31, 2018
Segment Reporting Information, Description of Products and Services	The Company product revenue includes industrial wireless products and accessories such as antennas, power supplies and cable assemblies. The Company also provides direct site support and engineering services to customers, such as repair and upgrade of its products.
Sales, net	$ 273,968	$ 374,166
Domestic sales revenues	241,975	292,193
Foreign sales	31,993	81,973
Sales order backlog	5,028	11,538
Manufactured Product, Other
Sales, net	252,968	369,389
Technology Service
Sales, net	$ 21,000	$ 4,777