Abstract: An opto-coupler and a process for fabricating an opto-coupler are disclosed. The opto-coupler includes at least one light-emitting diode and a photodiode for galvanically isolating electric circuits. The optical components are mounted in a yielding material, such as silicone rubber, in a housing. The interior walls are coated with a pigmented yielding coating which includes TiO2 to enhance light reflection inside the housing and increase the current transfer efficiency of the device. The opto-coupler has a high dielectric breakdown voltage and is immune to radiation. The device can be employed in space applications.

Abstract: According to a first embodiment of the invention, if an e-mail sender attempts to make too many connections within a predetermined period of time, the excess connections are automatically rejected. According to a second embodiment of the invention, an agreement is established between an e-mail sender and an e-mail recipient that states when the sender may send e-mail messages to the recipient. According to a third embodiment of the invention, trend data reflecting an amount of e-mail sent by a sender is collected. The trend data can be used to establish a rate limit for the sender. According to a fourth embodiment of the invention, separate rate limits are established for authenticated and unauthenticated mail from addresses. According to a fifth embodiment of the invention, a sender may have a rate at which their e-mail is transmitted reduced if they exceed predetermined rate limits.