Mobile radio telephone with direct communication capability

摘要

The two mobile telephones (1,2) usually communicate in the frequency band f1 with the fixed stations (FS1,FS2) of a network operator. One station suffices if the telephones are located near to one another. With these, equally equipped, telephones, should one telephone call the other, a second frequency f2 is used. The call contains, in coded form, the telephone numbers of the caller and the called party. The call can be received if the field strength is sufficiently large. When the call is answered, a communication can take place, as with ''walkie-talkie'' sets.