COOOJNICATIONS
SECTION 6.7
6.7.7
6.7.8
6.7.9
6.7.9.1
6.7.9.2
VER.V09F
USE IN TERMINAL EMULATION MODE
Although 2780 work stations are not generally interactive
devices, it is possible to use HUNTER in this mode when, for
example, testing the system with lDG ON cards, etc.
When in Terminal Emulation any received data is displayed on the
screen.
To transmit, a message character may be typed in directly.
Provided no mistakes are made, and there is less than 5 seconds
between each character, the message is sent on the transmission
channel.
COMMUNICATION ERROR
There are a number of different line errors which may occur when
using this protocol. These are detected and then displayed as
communications errors. An error number is also displayed. The
meaning of these error numbers is shown in section 6.7.5,
MESSAGE TRANSMISSION. If use of the ON COMMS statement is made
then the error number will be in the COMERR flag.
There is one exception to this rule, see Fig 6.2, UNANSWERED
LINE BID. This is the most usual error and will generally be
due to a connection fault, as no characters have been received.
The option is then given to: Retry transmission ?(Y/N) if 'Y' is
pressed then HUNTER.will send out up to 10 more ENQs (enquiries)
and the offer of retry made again.
If 'N' is pressed then the
error 01 is returned, and if programmed through ON COMMS,
returns control back to Basic.
ERROR MESSAGES:
Error 01: Unanswered line bid
This is due to not receiving any reply in a request for the
line, usually caused by incorrect connection of the
communications channel.
Error 02: No response from receiver
After establishing the line, a buffer has been sent to which no
response has been given, despite 10 ENQs having been sent.
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