5-42 Chapter 5: Programming
When you use an IBM terminal and the scanner detects a bad message
from the terminal, this parameter controls how the original message
gets transmitted again. If you scan the Hex 4 tag, the scanner transmits
the original message forever. If you scan the Hex 5 tag, the scanner
only retransmits the original message three times. After failing three
times, the scanner reinitiates communications and attempts to transmit
the tag data again. (Do not use this selection unless advised to do so by
NCR to solve a problem.) Retrying forever is the Default.
RS-232 Mode: Normal or Eavesdrop
The Eavesdrop Mode is a method of physical connection between the
RealScan 7892 and its host (PC) that places a “dumb CRT” between the
host and the scanner. This mode permits the RealScan 7892 to accept
input from the “dumb CRT” and then transmit the data on its own
transmit line to the host. (If the scanner receives data while it is
transmitting, the data is lost.) When using this mode, a special
Eavesdrop Mode cable is required. Data transmitted by the terminal is
sent to the RealScan 7892 and re-transmitted to the host. Data from the
host is sent to the "dumb CRT". The scanner sends its data to the host.
In Normal Mode, the RealScan 7892 transmits and receives directly
with the host. If you scan the Hex 6 tag, the scanner receives and
transmits to match the Normal RS-232 connection. If you scan the Hex
7
tag, the scanner receives and transmits to match the Eavesdrop
connection. Normal RS-232 connection is the Default.
RS-232 Delay
You can select three different delays between messages when using RS-
232 communications. If you do not want any delay, scan the Hex 8 tag.
Scan the Hex 9 tag for a 10-millisecond delay or the Hex A tag for a 50-
millisecond delay. Selecting the proper delay can ensure that all tag
data is received by the host. When using Handshaking, at least a 10 ms
delay should be used to ensure that the host has sufficient time to
exercise refusal of the next message. The default is 10 ms for the
RealScan 7892.
Summary of Contents for RealScan 7892
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