Description:
The VIP-335 “SmartPipe”™
Protocol Converters allow RS-232 data to be fed directly into
a PC’s keyboard port. A standard keyboard can also be connected
to the “SmartPipe”, and its output will be merged with
the RS-232 data forming a keyboard wedge. The keyboard is optional
and is not required for the VIP-335 to boot up and operate with
the PC.
Code Conversion for the VIP-335
The standard ASCII
code set, common in RS-232 applications, does not correspond
to the scan codes of the standard PC keyboard, requiring translation
between ASCII and PC keyboard codes . The Vetra Protocol Converters
offer switch selectable ASCII code to keyboard scan code translation.
With code translation enabled, the VIP-335 “SmartPipe”™
translates ASCII codes to equivalent PC keyboard scan codes as
shown in the "ASCII to PC Key Code Translation" Table. Note that the table contains
more codes than the standard ASCII set. These codes have been
added to bring the functionality of the PC keyboard into the
ASCII world. Simulation of simultaneous depression of some keys
is possible using the separate “make” and “break”
codes for the Control, Shift, and Alt keys. For instance, to
simulate the Left Alt F1 keys combination, hex codes 83, A0,
93 should be sent.
With code translation disabled every character received at the
input of the Converters is copied unaltered to the output. The
converters do only a voltage and protocol conversion between
the PC’s bit synchronous TTL level protocol, and the asynchronous
RS-232 protocol. The user is responsible for generating RS-232
data that is meaningful to the PC’s keyboard input. The
DB-9 connector on the VIP-335 receives data on pin 2, and controls
Clear-To-Send (CTS) on pin 7. Pin 5 is ground. For more information
on CTS behavior click here.
The VIP-335 uses the following RS-232 format. 1 start bit,
1 stop bit, 8 data bits, and no parity. There are four baud rates
to choose from 1200, 2400, 4800, and 9600 baud. |