COURIER HIGH SPEED MODEMS
4-10 Data Mode Operations
+++ Escape code operations. Once the modem is online to another
system, the only command it recognizes is an escape code of three
typed pluses, which forces the modem back to Command mode.
Do the following when issuing the command:
• Wait one second after sending the last item of data
• Type: +++
• Wait one second before typing any data
Do not type the AT prefix or a Carriage Return. The guard time
of one second before and after the code prevents the modem
from misinterpreting the occurrence of +++ in the transmitted
data stream.
If necessary, the character used in the escape code or the dura-
tion of the guard time can be changed by resetting Register S2
or S12. See the S-Register Summary in Appendix B.
In response to +++, the modem returns to Command mode.
However, it keeps the line open or hangs up, depending on the
setting of DIP switch 9:
DIP Switch 9 Response to +++
OFF Modem goes on hook (hangs up), sends NO
CARRIER result code (factory setting)
ON Modem maintains connection (Online-Command
mode), sends OK result code
The factory setting (OFF) forces an automatic disconnect when
you issue +++. One advantage of this is that you are not likely
to inadvertently run up an all-night phone bill.
Set DIP switch 9 ON if you want the modem to respond to +++
by entering Online-Command mode, enabling it to execute
commands and return online. (See the O command, next.)
WARNING: For unattended modem operations: in rare instances,
the modem may fail to recognize the +++ escape code sequence.
If you are running the modem under software control for
unattended operations, we suggest you use the sure fire method
of dropping the DTR signal from the computer or terminal for
at least 50 milliseconds, to avoid costly phone charges.
Methods of turning the DTR signal offfor example, closing the
communications portdiffer from one computer to another.
