EXHIBIT 12.1 COMMUNICATIONS INSTRUMENTS, INC. COMPUTATION OF RATIO OF EARNINGS TO FIXED CHARGES (IN THOUSANDS) (UNAUDITED) PREDECESSOR COMPANY ----------------------------------------------------- NINE 4.5 7.5 MONTHS MONTHS MONTHS YEAR YEAR YEAR YEAR 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 12/31/97 -------- ------- -------- -------- -------- -------- -------- Earnings (Loss) Before Taxes and Minority Interest............... $3,079 $141 $(999) $1,004 $(2,498) $2,782 $ 6,938 ------ ---- ----- ------ ------- ------ ------- Fixed Charges: Interest Charges...... 93 77 639 1,189 2,172 3,139 5,243 Amortization of Financing Costs...... -- -- 79 90 137 252 401 Environmental Interest............. -- -- -- -- -- 147 119 Estimated Interest Factor of Rental Expense.............. 30 17 8 21 40 272 351 ------ ---- ----- ------ ------- ------ ------- Total Fixed Charges. 123 94 726 1,300 2,349 3,810 6,114 ------ ---- ----- ------ ------- ------ ------- Total Earnings Available for Fixed Charges............ $3,202 $235 $(273) $2,304 $ (149) $6,592 $13,052 ====== ==== ===== ====== ======= ====== ======= Ratio of Earnings to Fixed Charges.......... 26.0x 2.5x N/A 1.8x N/A 1.7x 2.1x