V i t a l W e l l E l e c t r o n i c s P t e L t d
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CHAPTER II
CONFIGURATION MODE
This section describes the configuration and test commands supported by the
radio modem. In most cases, once the configuration is set it will not need to be
changed. Configuration is performed using a serial terminal, or appropriate
communication application.
All commands and command values accepted by the radio modem are described
in this section; any entries other than those listed here results in an invalid
command or argument error message.
The first step to configuring the Radio Modem is to put it in Configuration Mode
…
II.1 Entering Configuration Mode
A series of three consecutively typed characters, called an escape sequence,
forces the radio modem to exit data transfer mode and enter the modem
configuration mode. While in
Configuration Mode
, you can communicate directly
with the radio modem using a number of specific commands to configure and test
the radio modem.
The escape sequence is factory set to
‘
+++
’
(
No carriage return key is followed
). A
pause length of which is called the escape guard time (about 1s) must be
completed both before and after when escape sequence is entered. These three
'+' characters must
not
be sent as one continued frame. The delay between any 2
characters must be between 20ms~1s for the (
‘
+++
’
) sequence. This prevents
the radio modem from interpreting the escape sequence as data and the vice
versa. The guard time must also be met when the Radio Modem is initially
powered up.
Configuration changes are stored permanently in non-volatile memory within the
Radio Modem. Exiting Configuration Mode and returning back to data transfer
mode is accomplished by typing
“
ATO
”
at the command prompt. This will force a
soft reset of the Radio Modem resulting in any configuration changes taking
effect.
II.2 Command Format
VW modem
’
s parameters are set through the use of AT type commands sent on
the serial link.
'AT' commands complies with Hayes protocol used in PSTN modem standards.
This
‘
AT
’
protocol is used to configure the modem parameters, based on the
following principles :
