Note 9 - Segment Reporting - Segment Reporting Information (Details) - USD ($)	3 Months Ended		6 Months Ended
	Mar. 31, 2017	Mar. 31, 2016	Mar. 31, 2017	Mar. 31, 2016	Sep. 30, 2016
Sales	$ 11,294,756	$ 10,587,187	$ 23,390,582	$ 18,836,855
Gross profit	3,764,429	3,584,612	7,788,058	6,349,992
Operating income (loss)	87,004	328,209	513,809	424,964
Assets	55,371,450		55,371,450		$ 50,268,159
Operating Segments [Member] | Cable TV [Member]
Sales	4,996,965	6,018,891	11,571,790	11,023,888
Gross profit	1,755,059	1,906,675	4,155,401	3,485,946
Operating income (loss)	262,648	336,279	1,171,631	453,119
Assets	24,283,621		24,283,621		25,201,697
Operating Segments [Member] | Telco [Member]
Sales	6,363,466	4,601,172	11,903,442	7,918,903
Gross profit	2,009,370	1,677,937	3,632,657	2,864,046
Operating income (loss)	(175,644)	(8,070)	(657,822)	(28,155)
Assets	24,075,143		24,075,143		15,122,911
Intersegment Eliminations [Member]
Sales	(65,675)	$ (32,876)	(84,650)	$ (105,936)
Segment Reconciling Items [Member]
Assets	$ 7,012,686		$ 7,012,686		$ 9,943,551