LTC 8780 Series
The biphase control code generated by an Allegiant Series switcher can contain three types of
data — receiver/driver commands, Console Command Language (CCL) commands that control
the SatelliteSwitching® functions, and switcher/follower data. When used in the biphase to
RS-232 conversion mode, the LTC 8780 can be configured to selectively filter out each of
these data types. This feature can reduce the amount of data that must be transmitted over
the RS-232 interface. Utilization of this capability may be required in cases where a low baud
rate is being used to transmit the control code of a large switcher configuration having multi-
ple keyboards that are operating simultaneously.
As a subpart of its selective filtering capability, the LTC 8780 contains an address-matching
feature that can provide one of two functions — it can disable transmission of CCL commands
that do not match the selected address, or it can disable transmission of receiver/driver com-
mands outside of a 64-camera block defined by the selected address. In a Satellite Selector
Unit configuration, the LTC 8780 would be configured using the address matching feature so
that only CCL commands associated with that specific Satellite address are converted. In its
receiver/driver address matching configuration, it can be used to limit the amount of data (as
would be generated in a large switching system) from being transmitted over an RS-232 link
operating at a low baud rate.
The LTC 8780 can be configured to operate as a signal distribution unit with 15 separate
biphase code outputs. Either star or daisy chain wiring configurations may be used when con-
necting to the biphase outputs. Each output is capable of driving up to 8 receiver/drivers in a
daisy chain configuration up to 1500 m (5000 ft) using 1 mm
18 AWG) shielded twisted pair. In this signal distribution mode of operation, the biphase
input code can be selectively filtered for the desired types of data as described above for the
RS-232 to biphase operational mode.
The LTC 8780 Series provide a single RS-232 interface using two RS-232 interface connectors.
In most applications like those described below, only one of the two connectors is used. In a
Satellite Selector configuration, the CONSOLE interface of the LTC 8780 is connected to an
Allegiant CONSOLE port using the supplied cable. The interface connector labeled RS-232
provides a standard RS-232 interface for connection to a modem or other RS-232 compatible
device. The data rate of the RS-232 interface is user selectable for 1200, 2400, 9600, or 38400
baud.
Note: If the LTC 8780 is being used with variable speed receiver/driver control codes gener-
ated by an Allegiant Series matrix switcher, a baud rate of 2400 or higher must be used. When
the RS-232 interface involves modems, the LTC 8780 Series can be configured to send stan-
dard AT type commands to aid in establishing the communication link between the modems.
LED indicators are provided on the front panel to show RS-232 data being received, RS-232
data being transmitted, biphase data being received, biphase data being transmitted, and
power ON (see Figure 5.7 on page 25).
2.1
Features
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Bosch Security Systems, Inc.
Designed for various applications utilizing Allegiant Series Switchers
Convers Allegiant biphase control code to RS-232 and RS-232 to biphase
Provides satellite address decoding
Signal distribution mode provides 15 seperate outputs
Instruction Manual
Description | en
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(Belden 8760 or equivalent
F01U066145 | 1.0 | 2007.04
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