Tait T2000 SERIES II, Service Manual

Page: 132 / 150

8.15.8 T2000-A70 Data Modem Kit
M2000-00
31/12/97 Copyright TEL
Messages To The RU
If the RU receives a command without error, and all parameters are valid, then the com-
mand will be executed and an acknowledge will be returned to the DTE. If an error
arises, the DTE will be notified with an appropriate response.
The following Table describes the commands available to the DTE to control operation
of the RU.
Table 8.15.2 Messages To The Radio Unit
Command Description
Message
Comments
[IDENT] [PARAMETERS]
Go To
Channel This forces the RU to
change to another
(conventional) chan-
nel. g [CHANNEL NUMBER]
This is a string of characters
representing the new channel
number. The range of allowed
characters is 0 to 9 only, and
the maximum number of dig-
its is 3. Valid channel numbers
are 1 to [NUM CHANNELS]. The value of [CHANNEL
NUMBER]
must be valid
for the RU being control-
led. The range of allowed
values depends upon the
RU’s programming, type
and the link selections on
the data modem PCB (refer
to Section 8.15.3). The
maximum allowable
value is returned by the
‘Query’ command.
Query This requests the RU to
respond with a block
of data identifying the
type of RU attached,
and the version of
modem firmware. q None The Query data is returned
to the DTE as a ‘Query
Response’ message (refer
to “Messages from the
RU”).
Transmit This requests the RU to
broadcast a block of
data on the radio chan-
nel. b The data to broadcast is encoded
as binary data. Note that this
field may contain unprintable
ASCII characters (such as CR/
LF) and protocol command
characters (such as “
•
”).
The maximum length of
data that may be sent with
the ‘Transmit’ command is
111 characters.
Null This requests the RU to
return an acknowl-
edgement to the DTE.
The DTE can use this
command to check that
an RU is connected. n None