Ciprofloxacin and Levaquin (Levofloxacin) are in the same drug class (fluroquinolones). It makes sense that you would be allergic to both. You probably are allergic to other drugs in the same class such as moxifloxacinI, Ofloxacin, etc.s a fluoroquinolone, it is in the same class of agents as ciprofloxacin, enoxacin, levofloxacin, lomefloxacin, norfloxacin, and ofloxacin. Nalidixic acid is also a quinolone drug.
STC is calculated by taking the Transmission Loss (TL) values tested at 16 standard frequencies over the range of 125 Hz to 4000 Hz and plotted on a graph. Your curve (what you actually measured) is compared to standard STC reference curves (see appendix).
STC stands for Small-scale Technology Certificate. It is a scheme developed by the Federal Government to encourage more people to install renewable energy systems and to make it more affordable for everyone. You might find some people refer to them as a rebate. However this is really untrue.