1.7 TDM Routing Functions

TDM routing functions are used in time division multiplexing (TDM) bus configurations, which include the CT Bus and SCbus. A TDM bus is resource sharing bus that allows information to be transmitted and received among resources over multiple time slots.

TDM routing functions enable the application to make or break a connection between voice, telephone network interface, and other resource channels connected via TDM bus time slots. Each device connected to the bus has a transmit component that can transmit on a time slot and a receive component that can listen to a time slot.

The transmit component of each channel of a device is assigned to a time slot at system initialization and download. To listen to other devices on the bus, the receive component of the device channel is connected to any one time slot. Any number of device channels can listen to a time slot.

Note: When you see references to the SCbus or SCbus routing, this information also applies to the CT Bus. That is, the physical interboard connection can be either SCbus or CT Bus. The SCbus protocol is used and the SCbus routing API applies to all the boards regardless of whether they use an SCbus or CT Bus physical interboard connection.

A set of TDM routing functions exist for each Intel Dialogic library, such as fax (fx_ functions) and voice (dx_ functions). See the appropriate API Library Reference for more information on these functions.

ms_getxmitslot( )

returns the number of the TDM bus time slot connected to the transmit component of the station

ms_listen( )

connects the listen (receive) component of a station interface to a TDM bus time slot

ms_unlisten( )

disconnects the listen (receive) component of a station interface from a TDM bus time slot

Note: TDM routing convenience functions, nr_scroute( ) and nr_scunroute( ), are provided to make or break a half or full-duplex connection between any two channels transmitting on the bus. These functions are not a part of any library but are provided in a separate C source file called sctools.c located in the /usr/dialogic/sctools directory. The functions are defined in sctools.h. MSI functionality may be conditionally compiled in or out of these functions using the SC_MSI and SC_DTI defines in the makefile provided. Refer to the Voice API Library Reference for more details.

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