voice band signals onto tip 101 and ring 114 through feeding impedances 102 and 115 in both on hook or off hook state the dc voltages on tip and ring can vary between around 0 v to around u2212 60 v as defined in the specific co application requirement depending on whether balance or unbalance ringing is supported or not the dc supply to the drivers 103 and 116 can vary between around 50 v to 200 v any dc voltages from data drivers 108 and 112 are blocked by capacitors 106 and 113 from interfering with the dc voltages on tip 101 and ring 114 and vice versa drivers 103 and 116 can also only provide the conventional pots dc line signaling voltages and loop current without transmission of any voice band ac signal depending on the overall system architecture of the slic drivers 103 and 116 can only provide dc signals or dc and ac voice band signals simultaneously the differential drivers 108 and 112 are used to transmit ac signal onto tip 101 and ring 114 the ac signal can be dsl type data band signal only or the dsl type data band signal and the pots voice band signal simultaneously depending on the overall system architecture of the slic the type of ac signal can be dsl type signal only or dsl type plus voice band signals the differential drivers 108 and 112 transmit the ac signal onto tip 101 and ring 114 through feeding impedances 107 and 111 and capacitors 106 and 113.