Apparatus for judging quality of mobile data communication

An apparatus for judging a quality of mobile data communication, said apparatus being coupled to a modem which conducts the data communication, said apparatus comprising:

• (a) an electric field strength detector means for producing a signal having a value corresponding to a signal strength of a received electric field;
• (b) a data communication judgment means for sampling repeatedly said signal from said electric field strength detector means for a prescribed period of time and for subjecting it to arithmetic operation to average a result of the sampling, said data communication judgment means comparing the result with a predetermined judgment reference value of a communication limit in a data communication and for providing an output in response to the comparison;
• (c) a visible display means for indicating that said average of the samples is higher than said predetermined judgment reference value in response to the result of the comparison by said data communication judgment means;
• (d) an audible tone means for producing an audible tone to indicate that said average of the samples is equal to or less than said predetermined judgment reference value in response to the result of the comparison by said data communication judgment means;
• and
• (e) a digital output terminal means connected to said output of the data communication judgment means for outputting a predetermined digital control signal to the modem so as to control starting and stopping of the modem in response to the result of the comparison of the signal strength of the received electric field with the predetermined judgment reference value.