Bug 911055 - [zffos1.1][P3][Dailer]DuT doesn allow to dial a <<pause>>

Empty string shouldn't be valid so instead of {0, 50} it should be {1,50}

    /^(?!,)([0-9#+*,]){1,50}$/

Your test plus empty check

    var regex = /^(?!,)([0-9#+*,]){1,50}$/; console.log(regex.test('123') + ' ' + regex.test(',123') + ' ' + regex.test('1,23') + ' ' + regex.test('a123') + ' ' + regex.test(''));

Outputs: 

    true false true false false