USER'S GUIDE
OPERATING MODES
PK232UG Rev. B 9/86
4-12
65
4.5.4.2
Mode A (ARQ) Changeover (
+?
Command)
When you finish typing your comments or traffic to the other station and wish the dis-
tant station to transmit to you:
o
Don't
type
KKK
or anything like that!
o
Do
type a plus sign immediately followed by a question mark (
+?
)
+?
is a software changeover command that switches your system from "Information
Sending Station" (ISS) to "Information Receiving Station" (IRS) and switches the dis-
tant system from "Information Receiving Station" receive to "Information Sending Sta-
tion". Your distant partner will see the
+?
and begin typing comments or traffic.
NOTE:
When discussing ARQ operation, we use the terms "Information Sending
Station" and "Information Receiving Station" instead of "transmit" and "re-
ceive". In AMTOR ARQ operation both stations are rapidly switching between
transmit and receive. When you send "information", the distant station sends
back "control" signals that tell your PK-232 how your signals are being re-
ceived, how the link is behaving.
o
Don't bother with multiple call signs and "over-to-you" routines used in Baudot and
ASCII RTTY operation. Don't bother with "KKK" at the end of your turn – the system
does it all for you when you type
+?
.
The FCC requires station identification once every ten minutes. It's sufficient to begin
with
QRA (mycall)
or end your transmission with
QRA (mycall)
before the
+?
change-
over code.
4.5.4.3
Mode A (ARQ) Break-in (
ACHG
Command)
In Mode A (ARQ), when you're the "Information Receiving Station", you can use the
ACHG
command to break or interrupt the distant station's comments.
ACHG
is a soft-
ware command that forces both systems to reverse the "Information Receiving" and
"Information Sending" status at both ends of the ARQ link. As the "Information Receiv-
ing Station", you normally rely on the distant station to send the
+?
command to do the
changeover at the end of his comments.
4.5.4.4
End the Mode A (ARQ) Connect, Return to AMTOR Standby
When you've finished you "final finals" to the distant station and both stations are ready
to end the Mode A (ARQ) contact, you can end the contact and terminate the link in
several different ways:
o
Type
<CTRL-C>
to return to Command Mode. Then type
R
to break the link.
The
R
command breaks the ARQ link and returns your system to AMTOR Standby –
your station can be accessed by a distant station's transmission of your SELCAL.
R
can also be used to stop sending a SELCAL while trying to access a distant sta-
tion.