Programmable interface for a physiological signal recording device

In a Holter machine for recording a physiological signal including a first interface having a plurality of plugs, an amplifier having an input coupled to at least one of said plurality of plugs and an output, an analog-to-digital converter having an analog input operatively connected to said amplifier output to sample analog signals and convert sampled analog signals to a digital signal, and a processor operable to operate said analog-to-digital converter and process said digital signals to obtain a signal representative of said physiological signal and record said obtained signal in a memory, wherein the improvement comprises:

• a second interface having a second plurality of plugs, said second plurality of plugs including at least one digital signal plug and at least one mixed plug, said mixed plug having an input/output analog operating mode and an input/output digital operating mode and being operatively connected to said analog-to-digital converter;
• and
• a logic circuit connected to said mixed plug and said digital plug and to said processor, said logic circuit being operable to control a transmission of signals through said second interface.