Operating instructions

2.3 Connectors
The keyboard has three RJ11 connectors on the back of the
machine, a power supply connector, a configuration DIP
switch and a DB9 socket for connection with the Personal
Computer.
The VIDEO line controls the video system connected to the
keyboard. Lines A and B control the first and second
telemetry channel respectively. The dip-switches are used to
insert or remove the 120 Ohm termination load for each
RS485 line (see § 3.2 - RS485 and types of systems, pag.
14).
Power supply connector
2.4 Adjusting the contrast
On the bottom of the keyboard there is a hole to reach the trimmer for adjusting keyboard contrast.
Using a flat-headed screwdriver with a fine tip it is possible to adjust the trimmer until the best visibility is
obtained.
2.5 DIP switch
The back of the keyboard has a DIP switch that is used to insert/remove the load on the RS485 lines and to
allow connection to the Personal Computer.
Refer to§ 3.1 - Video line and telemetry lines, pag. 14 for further information about inserting the line loads.
DIP1
Keyboard programmable by PC
DIP2
Load on Telemetry line A
DIP3
Load on Telemetry line B
DIP4
Load on video line
ON: PC connection mode
OFF: normal mode
ON: load inserted
OFF: load removed
ON: load inserted
OFF: load removed
ON: load inserted
OFF: load removed
During normal keyboard operation DIP1 should be kept in the OFF position, otherwise it is
impossible to communicate with the devices connected to the VIDEO line connector.
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