Specifications

ISU AT Command Reference Phase I AT Commands
Iridium Proprietary Version 2.45
20 June 2011 31
5.60 +DS - Set Data Compression Function
Set Command: +DS=[<direction>[,<comp_neg>[,<max_dict>[,<max_string]]]]
Set the V.42bis data compression function.
<direction> can take on the following values:
0 No compression
1 Transmit only
2 Receive only
3 Both directions (default)
<comp_neg> can take on the following values:
0 Do not disconnect if V.42bis is not negotiated by the remote DCE as specified in
<direction> (default)
1 Disconnect if V.42bis is not negotiated by the remote DCE as specified in <direction>
<max_dict> can take on the following values: 512 to 2048. Default is 512.
<max_string> can take on the following values: 6 to 250. Default is 6.
Read Command: +DS?
Query the current data compression parameter settings. The response is in the form:
+DS: <direction>,<comp_neg>,<max_dict>,<max_dict>
Test Command: +DS=?
List the supported data compression parameters. The response is in the form:
+DS: (supported <direction>s),(supported <comp_neg>s,(supported
<max_dict>s),(supported <max_dict>s)
Data compression will not work if IRLP is in unacknowledged mode.
Note: The register is not updated right after the user requests new values because the requested values may
or may not be what IRLP will use once a data call is established due to negotiations with the other peer. If
the register is updated right away, this may give the user the impression that those values will be used
during the data call, but there is no guarantee that will be the case. The real values will only be known once
a data call is established and the negotiation phase is done. For that reason, the values are written to the
register only after a call is established and both sides have negotiated parameter values. The value of the
register will be reset to default value (3) after the call completed.
5.61 +DR - Data Compression Report Level
Set Command: +DR=[<mode>]
Set the data compression reporting level.
<mode> can take on the following values:
0 Disable data compression reporting (default)
1 Enable data compression reporting
If reporting is enabled, the following intermediate result codes are transmitted by the ISU:
+DR: NONE
No data compression.
+DR: V42B
Data compression in use in both directions.
+DR: V42B RD Data compression in use in receive direction only.