Trumeter 7954 and 7957 multi function programmable din rail time relay trumeter 7957 the trumeter 7957 is a multi function digital time relay offering 18 operating modes which can be easily configured on the 3 digit lcd display the 7957 features a wide timing range of 01 second to 999 hours to suit all applications with a clear indication of the changeover relay status via the front panel lcdthe 7957 comes in a compact 175mm din rail mountable case and can accept a wide range of operatin