7
Introduction
The Telecast AdderTM 882i System consists of two Adder 882i fiber optic
multiplexer/ demultiplexers that simultaneously send and receive multiple
intercoms, eight digital datas, and four remote relay closures in each direction.
These signals are transmitted on optical fibers. Audio levels for 4-Wires are set
up by internal DIP switches that set amplifier gain to accept either mic or line
levels. Digital inputs and outputs are RS-422 and RS-232 compatible signals.
Four of the digital connectors also provide contact closure input and output. The
other four connectors alternatively provide SONY CCU compatible interfaces. All
connections except fiber and coax I/O and power are made via the front panel.
See Figure 1.
ADDER 882i
™
INTERCOM/DATA SYSTEM
Telecast
MADE IN USA
Fiber Systems, Inc.
1 2 3 4
EXTERNAL
POWER
INTERNAL
RESERVE
RECEIVE
STATUS
AUXILIARY
4-WIRE
AUDIO I/O
+8 dBm MAX
DATA/TALLY
DATA/CCU
POWER
1 2 3 4 5 6 7 8
A B
A B
+8dBm MAX LEVEL
600 Ohm
AUXILIARY
4-WIRE
AUDIO I/O
RTS
2-Wire
GAIN IN
GAIN OUT
NULL
B A
POWER
PORTS
TERM
ON
OFF
d
w
Clear-Com
2-Wire
POWER
PORTS
TERM
ON
OFF
d
w
GAIN
IN
OUT
NULL
A B
+8dBm MAX LEVEL
600 Ohm
AUXILIARY
4-WIRE
AUDIO I/O
Figure 1: Front Panel of the Adder 882i
Within the Adder 882i unit, the intercom audio signals are first digitized and then
multiplexed with the digital data and control signals. The combined electrical
signal is converted to an optical signal, launched into the optical fiber and sent on
to a second Adder 882i. This second unit receives the optical signal, converts it
into an electrical data stream, demultiplexes the signals and restores the audio
signals to analog levels.
An internal Ni-Cad battery provides backup in the event of line power loss.
The Adder 882i is available with several optical options and configurations.
• Standard connection with bidirectional signals carried on two optical
fibers at either 1300 or 1550 nm.
• One fiber connection with optically combined bidirectional signals at
1300/1550 nm as shown in Figure 2.
In a standard two-fiber system, identical Adder 882i units are used at each
location. The units both transmit at 1300 nm on the Tx ST connector and receive
the 1300 nm signal on the Rx ST connector. They are connected by the two
fibers so that the optical output of each box is connected to the optical input of
the other.