VMUX-FUNCTIONAL DESCRIPTION

FUNCTIONAL DESCRIPTION

The operation of the system at the functional level is described here. Through each plug-in card, the signal processing is followed in PCM to line direction. The function in Line to PCM direction is vice-versa. The Block Diagram of the system is shown in figure

FUNCTIONAL DESCRIPTION

The two incoming PCM Streams P1 & P2, enters the TME Card via the Upper Card Connector, from the rear side of motherboard.

75Ω/120Ω operation selected by one Jumper & programming through the NMT.

The incoming streams are connected to the two separate Combined Line Interface Unit & Framer IC through line transformers, which give out two TTL level ST-Bus compatible VF & Signalling Streams.

The Combined Line Interface Unit & Framer IC carries out the Line equalisation, HDB3 to binary conversion, deframing, clock extraction, extraction of information on spare bits, alarms monitoring etc.

These TTL Level VF & Signalling Streams are further connected to VF & Signalling Cross Connect Switches respectively. These switches perform the TSI function on these streams as programmed by the user in the routing tables.

The Local add-drop channels are placed on the TDM1 & CAS streams, which are connected to various Line Cards through the system Bus. The other signals required for the operation of Line Cards are also generated in TME Card and are connected to Line Cards via the system Bus.

The TME Card Processor and the Line Card processors communicate with each other through IP Bus.

The clock priorities can also be set through NMT. The selected clock is also extended to the connector on the motherboard.

In the Line Cards the ST Bus compatible data & signalling information is suitably processed, according to the type of the User Interface Card.

The Loop Protection function of the equipment can be achieved by using LPC Card (Optional). This Card is used to protect the P1 & P2 streams carrying the traffic in case of any major failure in the network. It provides the protection to the main 2Mb stream in a manner that all nodes on the chain remain connected to each other on the omnibus channels. It uses two 2Mb streams one spare & one backup for providing the protection.