Automatic telephone stations TCS has numerous modifications (types), which are marked XXX, where X is any number from 0 to 9. Every type of station is different in its configuration of the provided modules and aimed for specific requirements. Duplicated cCS, working in HA setting (High Availability), is designed in places:

• Where the OTC conferences are located
• On sites with controlling operators ISDN
• In places of connection termination circuit on port E1 with signalling, transported via D-channel, with contiguous side equipment (example СМК30-КС) if operators exist on both sides of the connection.

Circuit (conference OTC) is organized under the «star» pattern. For small sites the solution is equipped with nonduplicated cCS on the level of network element, which serves for the local communication and connection of local subscribers and SL.

The solution is additionally equipped with two duplicated cCS. Both of them is used to reserve conferences OTC. In case of failure of one of the duplicated cCS, depending on geographical location, the other takes the workload of the circuits on itself.

Pic 1: Example of two sites depicts two typical sites. On the left is the duplicated site (communication house — controlling station), where the conferences OTC (circuits) are created. On the right typical station, for which nonduplicated cCS, equipped with all necessary interfaces.

 Image 1: An example of two objects