Specifications

TN789B radio controller
Issue 6 February 2007 239
The TN788C circuit pack is the audio processor for the Px64 multimedia conference bridge. The
TN788C circuit pack contains eight digital signal processors. The processors include four for
encoding and four for decoding. Each encoder/decoder pair is assigned to a Px64 endpoint to
process its audio channel. Connection to and from the audio of the endpoint is by way of a
TN787 multimedia interface port. This connection is through the TDM-bus timeslots.
Each of the eight digital signal processors communicate with the main processor on the circuit
pack through eight individual dual-port random access memory (DPRAMs). No read-only
memory (ROM) is available on this circuit pack. The DPRAM is used for program download.
TN789B radio controller
Note:
Note: This circuit pack is no longer sold.
The TN789B radio controller circuit pack is an interface between a switch and two Wireless
Fixed Base (WFB) radio units. This interface is used for the DEFINITY Wireless Business
System. The TN789B circuit pack contains a main processor to handle data line circuit (DLC)
and upper medium access (MAC) layers of firmware. The TN789B circuit pack also contains
two lower MAC processors. one processor for each radio interface. Each radio interface is
referred to as an I2 interface.
The I2 link is the connection between the radio controller (RC) and the WFB. The RC supports
up to two I2 links. Each link consists of three pairs of twisted-pair cable: the transmit pair, the
receive pair, and the local power pair. The transmit pair transfers WFB control and frame
information from the RC to the WFB. The receive pair transfers status and frame information
from the WFB to the RC. If the RC cannot provide power to the WFB, a third pair, to the WFB,
can supply local power. When possible, the transmit pair and the receive pair provide phantom
power from the RC to the WFB.
Each TN789B circuit pack includes a standard TDM-bus interface from a system, two radio
interfaces to two separate radio units, and two synchronization ports. In addition, two RS-232
interfaces provide for a debug terminal and for setting up the wireless terminal.