Specifications

Chapter 1 – AT Commands, S-Registers and Result Codes
Multi-Tech Systems, Inc. SocketModem MT5600SMI/MT5656SMI Reference Guide (S000306B) 37
Command: +DR Data Compression Reporting
Description: This extended-format numeric parameter controls whether or not the
extended-format +DR: intermediate result code is transmitted from the
modem to the DTE. S95 bit 5 is reset to 0 for +DR=0 and is set to a 1 for
+DR=1. The more recent setting of +DR or S95 bit 5, and the W command
setting, determines the actual data compression result code reporting (see
S95 Parameter and W Command).
Defined Values: +DR0 Data compression reporting disabled (no +DR result code
transmitted).
+DR1 Data compression reporting enabled (+DR result code
transmitted). (Default.)
Report Commands: +DR? Reports Current or Selected Values.
Response: +DR: <current value>
Example: +DR: 1 For the default setting.
+DR=? Reports Supported Range of Parameter Values.
Response: +DR: (<value> range)
Example: +DR: (0,1)
Intermediate Result Code: +DR: <type>
The +DR: <type> reported represents the current (negotiated or
renegotiated) modem-modem data compression type. If enabled, the
intermediate result code is transmitted at the point after error control
negotiation (handshaking) at which the modem has determined which data
compression technique will be used (if any) and the direction of operation.
The +DR intermediate result code, if enabled, is issued after the Error
Control Report (+ER) and before the final result code (e.g., CONNECT).
The format of this result code is:
Defined Values: <type> An alphanumeric code corresponding to the selected option:
NONE Data compression is not in use.
V42B V.42bis is in use in both directions.
V42B RD V.42 bis is in use in receive direction only V42B TD V.42 bis
is in use in transmit direction only V44 V.44 is in use in both
directions V44 RD V.44 is in use in receive direction only V44
TD V.44 is in use in transmit direction only ALT MNP 5
compression.
Example: +DR: V42B
Command: %C Enable/Disable Data Compression
Description: Enables or disables data compression negotiation. The modem can only
perform data compression on an error-corrected link. The parameter value,
if valid, is written to S41 bits 0 and 1.
Defined Values: %C0 Disables data compression. Resets S46 bit 1.
%C1 Enables MNP 5 data compression negotiation. Resets S46 bit 1.
%C2 Enables V.42 bis data compression. Sets S46 bit 1.
%C3 Enables both V.42 bis and MNP 5 data compression. Sets S46 bit
1. (Default.)
Result Codes: OK
ERROR