Exhibit12

L-3 Communications Holdings, Inc.and L-3 CommunicationsCorporationRatio of Earnings to Fixed Charges

|                                                                                     |  |                                                         |         |         |  |        |        |         |  |        |        |         |  |        |        |         |  |        |        |         |  |  |
|-------------------------------------------------------------------------------------|--|---------------------------------------------------------|---------|---------|--|--------|--------|---------|--|--------|--------|---------|--|--------|--------|---------|--|--------|--------|---------|--|--|
|                                                                                |  | Year Ended December31,                                  |
|                                                                                |  | 2005                                                    |         | 2004    |  | 2003   |        | 2002    |  | 2001   |
| Earnings:                                                                           |  | (inmillions, except ratio of earnings to fixed charges) |
| Income before income taxes and cumulative effect of a changein accounting principle |  | $                                                       | 788.3   |    |  | $      | 596.7  |    |  | $      | 433.8  |    |  | $      | 314.0  |    |  | $      | 186.2  |    |
| Add:                                                                                |  |                                                    |    |    |  |   |   |    |  |   |   |    |  |   |   |    |  |   |   |    |
| Interestexpense                                                                     |  |                                                    | 199.0   |    |  |   | 138.1  |    |  |   | 124.7  |    |  |   | 115.1  |    |  |   | 80.0   |    |
| Amortization of debtexpense                                                         |  |                                                    | 5.2     |    |  |   | 7.2    |    |  |   | 8.0    |    |  |   | 7.4    |    |  |   | 6.4    |    |
| Interest component of rentexpense                                                   |  |                                                    | 40.4    |    |  |   | 26.8   |    |  |   | 24.4   |    |  |   | 22.4   |    |  |   | 14.3   |    |
| Earnings                                                                            |  |                                                    | 1,032.9 |    |  |   | 768.8  |    |  | $      | 590.9  |    |  | $      | 458.9  |    |  | $      | 286.9  |    |
| Fixedcharges:                                                                       |  |                                                    |    |    |  |   |   |    |  |   |   |    |  |   |   |    |  |   |   |    |
| Interestexpense                                                                     |  |                                                    | 199.0   |    |  |   | 138.1  |    |  |   | 124.7  |    |  |   | 115.1  |    |  |   | 80.0   |    |
| Amortization of debtexpense                                                         |  |                                                    | 5.2     |    |  |   | 7.2    |    |  |   | 8.0    |    |  |   | 7.4    |    |  |   | 6.4    |    |
| Interest component of rentexpense                                                   |  |                                                    | 40.4    |    |  |   | 26.8   |    |  |   | 24.4   |    |  |   | 22.4   |    |  |   | 14.3   |    |
| Fixedcharges                                                                        |  | $                                                       | 244.6   |    |  | $      | 172.1  |    |  | $      | 157.1  |    |  | $      | 144.9  |    |  | $      | 100.7  |    |
| Ratio ofearnings to fixed charges                                                   |  |                                                    | 4.2     | x  |  |   | 4.5    | x  |  |   | 3.8    | x  |  |   | 3.2    | x  |  |   | 2.8    | x  |
|                                                                                     |

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