The signal channels are groomed off and sent to the telephony controller via the TransPath lines. The bearer channels are mulitiplexed to the network lines. The subscriber, network, and TransPath lines are all used only with a MUX and only in a classic TransPath configuration. Generally this is a V.35 card and these are V.35 lines. Note that V.35 cards have four interfaces on each one, and V.35 lines carry only one channel.
Channels can be both bearer and signaling.
Signaling channels are backhauled to the telephony controller. When you click on a line, the channels appear. To make the data easier to manage, it is displayed in groups of channels by usage. You can expand this node and see all channels individually. You can do this for a single channel, for one or more groups of channels, or for all channels on one or more lines.