Communications Instruments, Inc. Exhibit 12.1 Computation of Ratio of Earnings to Fixed Charges (In Thousands) (Unaudited) Predecessor Company -------------------- ------------------------------------------------------------------------------- | Pro Pro Nine | Forma Forma Months 4.5 Months | 7.5 Months Year Year Year Year 9 Months 9 Months 9 Months Ended Ended | Ended Ended Ended Ended Ended Ended Ended Ended 12/31/92 5/10/93 | 12/31/93 12/31/94 12/31/95 12/31/96 12/31/96 9/30/96 9/30/97 9/30/97 -------- ---------- | --------- -------- -------- -------- -------- -------- -------- -------- | Earnings (Loss) Before Taxes | and Minority Interest 3,079 141 | (999) 1,004 (2,498) 2,782 (3,550) 2,633 6,445 1,137 | Fixed Charges: | Interest on Debt 93 77 | 639 1,189 2,172 3,139 10,459 2,236 1,975 6,631 Amortization of Financing | Costs -- -- | 79 90 137 252 684 179 228 489 Environmental Interest -- -- | -- -- -- 147 147 116 89 89 Estimated Interest Factor | of Rental Expense 30 17 | 8 21 40 272 286 189 264 264 | Total Fixed Charges 123 94 | 726 1,300 2,349 3,810 11,576 2,720 2,556 7,473 | Total Earnings Available for | Fixed Charges 3,202 235 | (273) 2,304 (149) 6,592 8,026 5,353 9,001 8,610 | Ratio of Earnings to Fixed | Charges 26.0x 2.5x | N/A 1.8x N/A 1.7x N/A 2.0x 3.5x 1.2x N/A--Earnings are inadequate to cover fixed charges