Under heavy loading conditions, for example when a large number of channels show continuous activity due to voiceband data or Group III facsimile signals, the voice interpolation may not be able to operate within a satisfactory quality range – discontinuous signals such as speech being affected by competitive clipping of the initial part of the activity.
When numerous channels are active simultaneously, for instance with voiceband data or Group III facsimile signals, the voice interpolation might fail to maintain satisfactory quality – interruptions in signals such as speech can be exacerbated by overlapping clipping at the start of their activity.