the device does not accept dtmf codes for the dialing of telephone numbers then programming in pulse mode is imposed for this case set 108 to 0 if dtmf is permitted the set 108 to 1 it is pointed out that even if the telephone line does not permit dual tone the programming and commands for the device may be made in dual tone since the device integrates an internal dtmf decoder numerals 109 and 110 denote the two telephone numbers programmed for auto dialing the first digit of this series of numbers defines whether communication is to be made with a human 0 or an external modem 1 these numbers are dialed sequentially as will be later described by the respective algorithm if the call is local then the number dialed for example 555 5555 will be connected and the next four digits of the number will be ignored by the telephone company however if the first digit of the telephone number is a 1 then the number dialed is long distance and may be followed by a regional or area code such as 1 514 555 5555 the default number programmed in the system is a 34 no service 34 number all the option codes in fig1 b with the exception of 118 are part of the 34 on off 34 switching sub system with 111 112 and 113 being closely related option 112 is the 34 output contact arrangement 34 with 0 normally open and 1 normally closed considering that our system simply has two channels the right cell which is doubly framed always represents the second channel in certain applications of this sub system.