REMEMBER!
To leave the Programming
Mode at any time, press the
Esc
key. Doing so will
return the CP-220A to its
normal operating mode.
Programming changes will
be stored automatically.
PARAMETER 51:
XON
Default:
PARAMETER 46
is defaulted to [COMP FAIL TEST OFF].
Advancing to Next Parameter:
The next parameter in
Category C
is
PARAMETER 51.
Because it is not
sequential, it cannot be reached with a single press of the
key. To
advance to
PARAMETER 51,
press the
N
key.
The CP-220A displays the parameter just programmed ([PARAMETER
NUMBER 46]) with its first digit flashing, indicating its request for the
next parameter number.
You can reach
PARAMETER 51
by pressing the
5
and
1
keys.
XON 00 MM/DD/YY HH:MM:SS
Background:
Once the CP-220A receives and verifies a subscriber's message, it's passed
on to the
Automation System,
where it can be dispatched. In Central
Stations with many receivers feeding data to a single
Automation System,
there has to be a way to control the flow of data if the
Automation System's
computer should become too busy to accept it. A technique known as
Software Handshaking,
or
Flow Control,
allows the computer to send a
designated
ASCII
character back to the CP-220A that, in effect, says to the
receiver, "Stop sending data; I have to process what I've got." This
character, known as
XOFF,
is usually programmed as
ASCII
[19].
NOTE: See
PARAMETER 11
(on page 2-79) for information on
ASCII
coding and the
ASCII Character Set.
Once the computer is capable of receiving additional data, it sends another
character, known as
XON
, which is typically programmed as
ASCII
[17]. It
essentially says, "I'm ready now; send some more data."
PARAMETER 51
is used to program the
XON
character;
PARAMETER 52,
which follows on page 2-99, is used to program
XOFF.
Although this method of handshaking is useful for busy Central Stations, a
technique known as
Hardware Handshaking
(discussed in
PARAMETER
54)
performs the same function more efficiently by using dedicated voltage
levels carried by the cable connecting the computer with the receiver.
Programming Procedures:
After entering
PARAMETER 51,
[XON 00] will be displayed with the first
[0] after [XON] flashing. Although it's customary to use
ASCII
[17], any
value between [01] and [FF] may be programmed. Use
the
NEXT
key or the
CP-220A Central Station Receiver
Section 2: Programming the CP-220A Page 2-97
Hook-Up and Installation Manual