In addition to the Echo software, to record calls over PSTN, channels such as ISDN30 (PRI/E1/T1/J1), ISDN2 (BRI) or analogue POT lines, a piece of physical hardware is necessary to physically tap into your lines. The hardware is available in various form factors, in order to address various deployment needs. These hardware devices passively intercept your phone lines, monitoring and recording all calls that pass along your lines. The hardware is available in various form factors, in order to address various deployment needs.