360 Systems DigiCart/II Plus - Manual (Page 31)

DigiCart/II Plus Owner's Manual Controls and I/O • 19
Rear Panel Interfaces
Several of the most useful standards have been selected to interface DigiCart/II Plus with
professional audio-video equipment and allow functioning with existing automation systems and
simplify the development of new and custom applications. Detailed technical information about the
interfaces will be found in the Appendices.
Serial Control
An EIA-485 (RS-485) serial port is included on the rear panel. All of the functions of DigiCart/II
Plus can be accessed and controlled via this serial port. EIA-485 is a multi-drop version of the
EIA-422 specification, and is fully compatible.
The serial port provides bi-directional communication with DigiCart/II Plus. The port utilizes an
EIA-485 electrical standard with an ES-Bus protocol and with properly terminated lines can
communicate over 1,000 meters. Specifics of this can be found in Appendix B, Serial Control
Protocol. The following pinout is used on serial port:
PIN SIGNAL
1 GND
2
+5 VOLTS (Not normally used)
3 GND
4 TX
+
5 TX –
6 HSK OUT (Not normally used)
7 HSK IN (Not normally used)
8 RX +
9 RX -
Transport Controls
The PLAY, STOP and RECORD remote control inputs are optically isolated from DigiCart/II's
circuitry; a common floating return is provided. +12V may be sourced from pin 17, or provided
from an external source. Current limiting devices are provided within DigiCart/II Plus so that
voltage may be applied directly between ground on pin 4, and either the PLAY, STOP or RECORD
control inputs.
NOTE: If +12V is sourced from DigiCart/II Plus, the optical isolators no longer provide isolation.
Refer to the partial schematic of the DigiCart/II interface circuits in Appendix A, Interface
Schematics.
Transport Lamps/Tally Outputs
PLAY, STOP and RECORD lamps are 12-volt incandescent bulbs having +12V connected to one
side. An open-collector transistor is used to bring the low side to ground to turn the lamp on. This
transistor is used for the lamps internal to the DigiCart/II Plus, and for external lamps on remote
switches. +12V is available on pin 17 of the remote connector for use with external lamps. Refer
to the schematic of DigiCart/II's interface circuits in Appendix A.
Cue Output — Secondary
Just as with NAB analog tape carts, cue markers are provided for triggering the PLAY buttons on
other machines, or as an "alert" or end-of-message cue. For applications other than broadcast, they