MTCMR-G-F4 Multi-Tech Systems, MTCMR-G-F4 Datasheet - Page 27

• Manufacturer Part Number: MTCMR-G-F4
• Description: MODEM GPRS QUAD BAND GSM GLOBAL
• Manufacturer: Multi-Tech Systems
• Series: MultiModem® iCellr

Specifications of MTCMR-G-F4

• Frequency: 850MHz, 900MHz, 1.8GHz, 1.9GHz
• Applications: General Purpose
• Interface: RS-232, USB
• Function: Transceiver, Modem
• Data Rate - Maximum: 115.2kbps
• Modulation Or Protocol: GSM, GPRS
• Voltage - Supply: 9 V ~ 32 V
• Package / Case: Module with Case
• Lead Free Status / RoHS Status: Lead free / RoHS Compliant
• Features: -
• Power - Output: -
• Sensitivity: -
• Lead Free Status / RoHS Status: Lead free / RoHS Compliant, Lead free / RoHS Compliant
• Other names: 881-1151; MTCMR-G-F4

Echo Cancellation +ECHO
Multi-Tech Systems, Inc. GPRS AT Commands Reference Guide (Document Number S000293J)
Description:
Values:
This command enables, disables or configures the Echo Cancellation functions for voice calls (in rooms,
in cars, etc.).
It is necessary to tune the Microphone gain (AT+VGT) and the Speaker gain (AT+VGR) before
activating the Echo Cancellation.
Notes:
<mode>
<status>
<AlgoId>
•
•
•
0
1
0
1
2
3
Note: <Status> does not indicate the currently selected speaker. If Echo is activated, it indicates
the speaker for which Echo parameters are set. Echo can be activated on a non-selected speaker.
1
6
Note that Echo Cancellation algorithms may not be available on some modems. Refer to the
description above.
•
•
You can activate/deactivate the echo cancellation during a call without resetting the product if
the <Algold> parameter is not changed, but have to used the syntax with all parameters:
AT+ECHO=1,6,30,8000,256 for instance.
To use Echo Cancellation 6, the ECHO feature must be activated.
Note that Echo Cancellation algorithms may not be available on some modems:
Deactivate Echo
Activate Echo
When mode = 1 is choosen, AlgoId is mandatory.
Echo Deactivated
Echo Activated for Mic/Spk One
Echo Activated for Mic/Spk Two
Reset the product
Echo cancellation 1
Echo cancellation 6: AEC algorithm
Echo Cancellation 1 (4 parameters):
♦
♦
♦
♦
Echo Cancellation 6 (12 parameters):
♦
♦
♦
Modem
Q24 Plus (AMR)
<Step> Specifies the attenuation step between attenuation and no attenuation.
<PcmThRel> Specifies the relative threshold between max and min energy information.
<PcmThMax> Specifies threshold of max energy information.
<Volout> Specifies the maximum attenuation of the switch
0
1
2
3
…
14
15
0
1
2
3
The allowed range is [0 - 31]. Default = 10.
The allowed range is [0 - 31]. Default = 7.
<AlgoParam> High value leads to high echo attenuation but the full-duplex quality will be
less efficient.
The allowed range is [ 0 - 63 ]. (30 by default)
<NoiseThres> indicates the noise threshold. Low value leads to high noise attenuation.
The threshold 32767 indicates no noise attenuation. The allowed range is [0 - 32767].
The default is 50. The values above 512 have no effect (noise reduction will be disabled)
<NmbTaps> indicates the Number of Taps of the Adaptive Filter. The allowed range is [2 -
256].
The default is 256.
64 taps = short Echo
256 taps = long Echo
31 db (default)
29 db
27 db
25 db
3 db
1 db
1 db
2 db
3 db
4 db (default)
Algorithm 6 Support
Yes
Algorithm 3 Support
No
Chapter 5 – Call Control Commands
27