The CTP Series supports the following modules for extending analog service from the PBX voice switch to remote locations for remote phone extensions or for accessing central office (CO) dial-tone or other services:
FXS and FXO interfaces support two types of signaling:
Normally a 2W-FXS interface connects to a 2W-FXO interface across the IP network. However, you can connect two interfaces of the same type by using private line automatic ringdown (PLAR) signaling. With PLAR, two handsets are directly connected so that when someone picks up a handset, the handset at the remote end starts to ring. There is no call routing (dialing) involved. You can enable PLAR on VComp bundles for modules that are configured for loop-start signaling. Both ends of the VComp bundle must have PLAR enabled.