Quectel EC25 User Manual

LTE Module Series
EC25&EC21 AT Commands Manual
EC25&EC21_AT_Commands_Manual 191 / 231
Parameter
Example
ATD12345678900; //Dial
OK
<Call connect>
AT+VTS="1" //The remote caller can hear the DTMF tone
OK
AT+VTS="1234567890A" //Send multiple tones at a time
OK
12.5. AT+VTD Set Tone Duration
The command sets the duration of DTMF tones. It can also set time interval of two tones when sending
multiple tones at a time.
Reference
3GPP TS 27.007
<dtmfstring> ASCII characters in the set 0...9, #, *, A, B, C, D. The string should be
enclosed in quotation marks ("...").
When sending multiple tones at a time, the time interval of two tones
<interval> can be specified by AT+VTD. The maximal length of the string is
31.
<duration> The duration of each tone in 1/10 seconds with tolerance.
The value ranges from 0 to 255.
If the duration is less than the minimum time specified by the network, the
actual duration will be the network specified time.
If this parameter is omitted, <duration> is specified by AT+VTD.
AT+VTD Set Tone Duration
Test Command
AT+VTD=?
Response
+VTD: (0-255),(0-255)
OK
Read Command
AT+VTD?
Response
+VTD: <duration>,<interval>
OK

Quectel EC25 Specifications

General

Category	LTE Module
LTE TDD	B38/B40/B41
WCDMA	B1/B5/B8
GSM	850/900/1800/1900 MHz
Data rates	LTE Cat 4: 150 Mbps DL/50 Mbps UL
GNSS	GPS/GLONASS/BeiDou/Galileo/QZSS
Operating Temperature	-40°C to +85°C
Form Factor	LCC
Storage Temperature	-45°C to +90°C
SIM Interface	1.8V/3.0V
Antenna Interface	Main, Diversity, GNSS
LTE FDD	B1/B3/B5/B7/B8/B20
Interfaces	USB 2.0, UART, PCM, GPIO
Operating Voltage	3.3V - 4.3V
Protocols	TCP/IP, UDP, FTP, HTTP, HTTPS
Certifications	CE, FCC, PTCRB, GCF, RCM, IC