Texas		75-1815822
(State of Incorporation)		(I.R.S. Employer Identification No.)
3000 Research Drive Richardson, Texas		75082
(Address of principal executive offices)		(Zip Code)

Common Stock, $0.01 Par Value (Title of Each Class)

11,141,213 (Number of Shares Outstanding at October 31, 2002)

				Page Number
Part I.		Financial Information (Unaudited)
Item 1.		Consolidated Balance Sheets at September 30, 2002 and March 31, 2002		3
		Consolidated Statements of Operations for the Three and Six Months Ended September 30, 2002 and 2001		4
		Consolidated Statements of Cash Flows for the Six Months Ended September 30, 2002 and 2001		5
		Notes to Consolidated Financial Statements		6
Item 2.		Management’s Discussion and Analysis of Financial Condition and Results of Operations		11
Item 3.		Quantitative and Qualitative Disclosures About Market Risk		18
Item 4.		Controls and Procedures		18
Part II.		Other Information
Item 4.		Submission of Matters to a Vote of Security Holders		19
Item 6.		Exhibits and Reports on Form 8-K		19
		Signatures		21
		Certifications		22

		(Unaudited) September 30,				March 31,
ASSETS		2002				2002
Current assets:
Cash and cash equivalents		$	2,816,288			$	1,245,452
Receivables, less allowance for doubtful accounts of $816,000 at September 30, 2002 and $1,130,000 at March 31, 2002			9,873,130				13,579,304
Inventories			10,796,602				11,700,211
Income tax receivable			101,451				1,908,225
Prepaid expenses			1,016,293				859,875
Other current assets			57,934				—
Total current assets			24,661,698				29,293,067
Property and equipment, at cost, net			7,934,343				8,265,011
Deposits and other			357,345				312,242
Goodwill, less accumulated amortization of $1,098,000 at September 30, 2002 and March 31, 2002			70,634				70,634
Total assets		$	33,024,020			$	37,940,954
LIABILITIES AND SHAREHOLDERS’ EQUITY
Current liabilities:
Accounts payable		$	5,121,835			$	7,295,345
Current portion of long-term debt			1,021,450				1,021,450
Line of credit			4,000,000				7,600,000
Accrued compensation			1,306,833				1,400,564
Accrued restructuring costs			204,424				448,495
Accrued sales commissions			457,856				600,056
Other accrued expenses			2,727,584				2,773,084
Total current liabilities			14,839,982				21,138,994
Long-term debt			510,725				1,013,002
Commitments and contingencies
Shareholders’ equity:
Preferred stock, $0.01 par value:
Authorized shares — 10,000,000
Issued shares — none			—				—
Common stock, $0.01 par value:
Authorized shares — 40,000,000
Issued shares — 11,637,689 at September 30, 2002 and 11,583,525 at March 31, 2002			116,377				115,835
Additional paid-in capital			24,333,344				24,257,894
Retained deficit			(2,308,124	)			(4,116,487	)
Less treasury stock (496,476 shares)			(4,468,284	)			(4,468,284	)
Total shareholders’ equity			17,673,313				15,788,958
Total liabilities and shareholders’ equity		$	33,024,020			$	37,940,954

		Three Months Ended September 30,								Six Months Ended September 30,
		2002				2001				2002			2001
Commercial system sales		$	19,747,261			$	19,970,481			$	37,594,516		$	37,390,054
Residential system sales			2,479,146				3,035,753				4,827,169			7,339,165
Total sales			22,226,407				23,006,234				42,421,685			44,729,219
Cost of sales			10,829,838				13,874,707				20,799,087			24,472,331
Gross profit			11,396,569				9,131,527				21,622,598			20,256,888
Selling and marketing expenses			5,208,224				8,264,220				10,770,142			15,360,028
Research and development expenses			2,439,087				1,938,295				4,390,849			3,833,258
Restructuring costs			—				(46,463	)			—			(89,742	)
General and administrative expenses			2,177,180				2,551,188				4,207,956			4,243,099
Total operating expenses			9,824,491				12,707,240				19,368,947			23,346,643
Operating income (loss)			1,572,078				(3,575,713	)			2,253,651			(3,089,755	)
Interest expense			110,186				223,509				242,703			409,367
Other income (expense), net			(2,183	)			(96,662	)			8,797			(87,011	)
Income (loss) before income taxes			1,459,709				(3,895,884	)			2,019,745			(3,586,133	)
Income tax provision			141,334				4,237,208				211,382			4,345,621
Net income (loss)		$	1,318,375			$	(8,133,092	)		$	1,808,363		$	(7,931,754	)
Basic earnings (loss) per share		$	0.12			$	(0.74	)		$	0.16		$	(0.72	)
Diluted earnings (loss) per share		$	0.12			$	(0.74	)		$	0.16		$	(0.72	)

		Six Months Ended September 30,
		2002				2001
Operating Activities
Net income (loss)		$	1,808,363			$	(7,931,754	)
Adjustments to reconcile net income (loss) to net cash provided by (used in) operating activities:
Depreciation			1,664,715				2,126,736
Amortization			—				333,980
Write-down of demonstration equipment			—				708,813
Write-down of goodwill			—				90,197
Provision for losses on receivables			262,045				515,322
Provision for inventory obsolescence			354,357				2,636,092
Deferred income taxes and valuation allowance			—				4,331,632
Changes in operating assets and liabilities:
Receivables			3,444,129				(2,514,803	)
Inventories			549,252				(1,659,171	)
Prepaid expenses and other assets			(227,370	)			(160,660	)
Accounts payable			(2,173,510	)			2,020,530
Other accrued expenses			(525,502	)			(793,965	)
Income taxes			1,806,774				—
Net cash provided by (used in) operating activities			6,963,253				(297,051	)
Investing Activities
Purchase of property and equipment			(1,366,132	)			(2,189,768	)
Net cash used in investing activities			(1,366,132	)			(2,189,768	)
Financing Activities
Sale of common stock — net proceeds			75,992				591,782
Net increase (decrease) in line of credit