A process is proposed for preparing isocyanates by thermally cleaving carbamates to obtain a carbamate cleavage gas comprising the corresponding isocyanate and the corresponding alcohol, which comprises quenching the carbamate cleavage gas in the presence of an ether which functions as an inhibitor for the reverse reaction of the isocyanate with the alcohol. The audio receiver is configured for digital wireless communication with the audio transmitter. Thus, when a timer of the visual alert device reaches each of the preliminary follow-up time value, the primary follow-up time period, and the final follow-up time value, the corresponding color segments are illuminated to indicate the current response priority level. The request is then analyzed to determine what resources are necessary to manage the virtual server.