A signal transmission device comprising an encapsulated segment produced by a method which comprises contacting the segment of the signal transmission device with an effective amount of a room-temperature curable composition comprising: (1) a hydroxy-functional compound having a molecular weight of greater than 500 and a hydroxy functionality of 2 or more; (2) an epoxy-functional compound having an epoxy functionality of 2 or more; and (3) a curative catalyst, in an amount effective to crosslink the epoxy and hydroxy components of the respective epoxy-functional and hydroxy-functional compounds.