Ebyte E49-900T20S User manual

E49-900T20S User Manuel
868MHz/915MHz SMD Wireless Module

Copyright ©2012–2021，Chengdu Ebyte Electronic Technology Co.,Ltd.
CONTENTS
DISCLAIMER......................................................................................................................................3
1. OVERVIEW..................................................................................................................................... 4
1.1 INTRODUCTION..............................................................................................................................................................4
1.2 FEATURES...................................................................................................................................................................... 4
2. SPECIFICATION AND PARAMETER........................................................................................ 5
2.1 LIMIT PARAMETER......................................................................................................................................................... 5
2.2 OPERATING PARAMETER................................................................................................................................................ 5
3. SIZE AND PIN DEFINITION........................................................................................................6
4. RECOMMENDED WIRING DIAGRAM.....................................................................................7
5. FUNCTION DESCRIPTION..........................................................................................................8
5.1 MODULE RESET............................................................................................................................................................. 8
5.2 AUX DETAILED EXPLANATION...................................................................................................................................... 8
5.2.1 Wireless receiving indication................................................................................................................................. 8
5.2.2 Wireless transmission indication........................................................................................................................... 8
5.2.3 Reset and exit sleep mode...................................................................................................................................... 9
5.2.4 AUX Precautions................................................................................................................................................... 9
5.2.5 Detailed explanation of fixed-point mode.............................................................................................................. 9
5.2.6 Broadcast transmission....................................................................................................................................... 10
5.2.7 Broadcast address................................................................................................................................................ 10
5.2.8 Monitor Address.................................................................................................................................................. 11
6. OPERATING MODE.................................................................................................................... 11
6.1 MODE SWITCHING....................................................................................................................................................... 11
6.2 TRANSMISSION MODE（MODE0）..............................................................................................................................12
6.3 RSSI MODE（MODE1）.............................................................................................................................................12
6.4 SETTING MODE（MODE2）....................................................................................................................................... 13
6.5 SLEEP MODE（MODE3）........................................................................................................................................... 13
6.6 FAST COMMUNICATION TEST...................................................................................................................................... 13
7. COMMAND FORMAT.................................................................................................................14
7.1 DEFAULT PARAMETERS...............................................................................................................................................15

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7.2 READING OPERATING PARAMETER..............................................................................................................................15
7.3 READING VERSION NUMBER READING........................................................................................................................ 15
7.4 PARAMETER SETTING INSTRUCTION............................................................................................................................15
8. HARDWARE DESIGN................................................................................................................. 18
9.1 COMMUNICATION RANGE IS TOO SHORT......................................................................................................................19
9.2 MODULE IS EASY TO DAMAGE.....................................................................................................................................19
9.3 BER(BIT ERROR RATE)IS HIGH..................................................................................................................................19
10. WELDING OPERATION GUIDANCE....................................................................................20
10.1 REFLOW SOLDERING TEMPERATURE.........................................................................................................................20
10.2 REFLOW SOLDERING CURVE..................................................................................................................................... 20
13 BATCH PACKAGING................................................................................................................ 21
REVISION HISTORY...................................................................................................................... 21
ABOUT US......................................................................................................................................... 21

Chengdu Ebyte Electronic Technology Co., Ltd E49-900T20S User Manual
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Disclaimer
EBYTE reserves all rights to this document and the information contained herein.
Products, names, logos and designs described herein may in whole or in part be
subject to intellectual property rights. Reproduction, use, modification or disclosure to
third parties of this document or any part thereof without the express permission of
EBYTE is strictly prohibited.
The information contained herein is provided “as is” and EBYTE assumes no
liability for the use of the information. No warranty, either express or implied, is given,
including but not limited, with respect to the accuracy, correctness, reliability and
fitness for a particular purpose of the information. This document may be revised by
EBYTE at any time. For most recent documents, visit www.ebyte.com.

Chengdu Ebyte Electronic Technology Co., Ltd E49-900T20S User Manual
Copyright ©2012–2021，Chengdu Ebyte Electronic Technology Co.,Ltd.
1. Overview
1.1 Introduction
E49-900T20S is an ultra-high cost-effective wireless module launched by
Chengdu Ebyte. It has 4 operating modes. Each transmission mode has its own
characteristics and can be applied to various application scenarios. E49-900T20S
can perfectly support industrial-grade applications, and undergoes rigorous testing
at the factory to ensure its industrial reliability and batch consistency.
The E49-900T20S supports a maximum transmission power of 20dBm. Users
can set a lower output power to save power consumption. The module works at
868-915MHz, with TTL level output, and is compatible with 3.3V. The module has data encryption function. The data
transmitted by the module in the air is random. Through strict encryption and decryption algorithms, the data interception
is meaningless, the probability of interference is reduced, and the reliability and transmission efficiency are improved.
Besides, it is a low-cost wireless serial transceiver module.
1.2 Features
The measured communication distance can reach 2.5km;
Maximum transmit power is 100mW, software can be adjusted in multiple stages;
The global license-free ISM 868MHz/915MHz;
Data transmission rate :1.2Kbps～200Kbps;
Low power consumption mode, suitable for battery application;
Advanced ultra-narrowed GFSK modulation;
2.6V~5.5V power supply;
Industrial-grade standard design, support long-term use of -40 ~ 85°C;
Support stamp hole and IPEX interface, users can choose to use according to their needs.
1.3 Application Scenario
Wearable devices;
Security system, Positioning system;
Wireless remote control, unmanned drone;
Health care product；
Wireless voice, wireless headphones;
Automobile industry application.

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2. Specification and parameter
2.1 Limit parameter
Main parameter
Performance
Remark
Min.
Max.
Power supply（V）
0
5.5
Voltage over 5.5V will cause permanent
damage to module
Blocking power（dBm）
-
10
Chances of burn is slim when modules
are used in short distance
Operating temperature（℃）
-40
85
2.2 Operating parameter
Main parameter
Performance
Remark
Min.
Typ.
Max.
Operating voltage（V）
2.6
5
5.5
Over 5.5V will permanently damage
module
Communication level（V）
3.3
For 5V TTL, it may be at risk of burning
down
Operating temperature（℃）
-40
-
80
Industrial design
Operating frequency（MHz）
850
868
930
Support ISM band
Power
consumption
TX current（mA）
97.9
Instant power consumption
RX current（mA）
12.04
Sleep current（μA）
1.3
Software is shut down
Max Tx power（dBm）
-
-
20.0
Receiving sensitivity（dBm）
-114
-115
-116
Air data rate is1.2kbps
Air data rate（bps）
1.2k
2.4k
200k
Controlled via user’s programming
Main parameter
Description
Remark
Distance for reference
2500m
Test condition：clear and open area, antenna gain:
5dBi,antenna height:2.5m，air data rate:1.2kbps
FIFO
54 Byte
Maximum capacity of single transmission, auto-sub-packing
when exceeding
Cache capacity
500 Byte
Modulation
GFSK
Communication interface
UART serial port
Package
SMD
Connector
1.27mm
Size
26*16mm
Antenna
IPEX/Stamp hole
50 ohm impedance

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3. Size and pin definition
No.
Name
Direction
Function
1
GND
Module ground wire
2
GND
Module ground wire
3
GND
Module ground wire
4
GND
Module ground wire
5
M0
Input（pull up when
it’s weak）
Cooperate with M1 to determine 4 operating modes of the module(can be lifted
floating, the module contains pull-up resistor）
6
M1
Input
（pull up when
it’s weak）
Cooperate with M0 to determine 4 operating modes of the module(can be lifted
floating, the module contains pull-up resistor）
7
RXD
Input
TTL serial input, connect to external TXD output pin;
8
TXD
Output
TTL serial input, connect to external RXD output pin;
9
AUX
Output
Used to indicate the working status of the module; the user wakes up the external
MCU and outputs a low level during the power-on self-test initialization
10
VCC
Module power supply positive reference, voltage range: 2.6V ~ 5.5V DC
11
GND
Module ground wire
12
NC
13
GND
Module ground wire
14
NC
15
NC

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16
NC
17
NC
18
NC
19
GND
Module ground wire
20
GND
Module ground wire
21
ANT
antenna
22
GND
Module ground wire
4. Recommended wiring diagram
No.
Brief introduction of connection between the module and the single-chip microcomputer (the above picture uses
STM8L single-chip microcomputer as an example)
1
The wireless serial port module is TTL level, please connect with MCU with TTL level.
2
Some 5V microcontrollers may require 4 ~ 10K pull-up resistors on the TXD and AUX pins of the module.

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5. Function description
5.1 Module reset
After the module is powered on, AUX will immediately output a low level and perform a hardware self-test and set
the operating mode according to user parameters. In this process, AUX is kept at a low level, outputs a high level after
completion, and starts to work normally according to the working mode composed of M1 and M0. Therefore, users need
to wait for the rising edge of AUX as the starting point for the normal operation of the module.
5.2 AUX detailed explanation
AUX is used for wireless sending and receiving buffer indication and self-inspection indication.
It indicates whether the data of the module that has not been transmitted through the wireless, or whether it has
received wireless data that has not been transmitted through the serial port, or the module is in the process of initial
self-test.
5.2.1 Wireless receiving indication
After receiving the valid wireless data, the module will immediately pull AUX low and start the serial port to output
data and then pull up AUX after the data output is completed.
5.2.2 Wireless transmission indication
After receiving the serial port data, the module will immediately pull down AUX and start sending data wirelessly
and after all the data is sent, pull up AUX.

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5.2.3 Reset and exit sleep mode
Only when resetting and exiting sleep mode
5.2.4 AUX Precautions
The function 1 and function 2 mentioned above have low output priority, that is, if any output low condition is met,
AUX outputs a low level; when all low level conditions are not met, AUX outputs a high level.
When the AUX output is low, it indicates that the module is busy, and the operating mode detection will not be
performed; when the AUX output is high, the mode switching will be completed.
When the user enters other modes from mode 3 (sleep mode) or during the reset process, the module will reset the user
parameters, during which AUX outputs low level.
5.2.5 Detailed explanation of fixed-point mode

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5.2.6 Broadcast transmission
5.2.7 Broadcast address
Example:
Set the address of module A to 0xFFFF and the channel to 0x04
When module A is used for transmission (same mode, transparent transmission mode), all receiving module
under the 0x04 channel can receive data to achieve the purpose of broadcasting.

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5.2.8 Monitor Address
Example: Set the address of module A to 0xFFFF and the channel to 0x04.When module A is used as a receiver,
it can receive all the data under the 0x04 channel to achieve the purpose of monitoring.
6. Operating mode
The module has four operating modes, which are set by pins M0 and M1; details are shown in the table below.
Mode（0-3）
M
M1
M
M0
Mode introduction
Remark
0
Transmission
mode
0
0
0
0
The serial port opens and wireless on, the module performs
data transmission according to the set transmission mode
The transmission method
of the sender and receiver
must be consistent
1
RSSI mode
0
0
1
1
Wireless off and the serial port opens, the module outputs
RSSI signal strength value at 100ms timing
Relative intensity values
only
2
Setting mode
1
1
0
0
Wireless off, can receive serial port command, refer
Command List, fixed baud rate 9600，8N1
Parameter configuration
3
Sleep mode
1
1
1
1
The module goes to sleep standby mode, and the serial port
and wireless are turned off.
Ultra-lower power sleep
6.1 Mode switching
Users can combine M0 and M1 with high and low levels to determine the operating mode of the module. Users
can use the MCU’s 2 GPIOs to control the node switching; after changing M0,M1: the module is idle and after
1ms, it can start working according to the new operating mode; if the module has not transmitted serial port
data via wireless, then entering the new operating mode after the transmission completed; if the module
receives the wireless data and sends out the data through the serial port, it needs to finish sending before
entering the new operating mode; if the module; so the mode switching can only be effective when AUX
outputs 1, otherwise the switch will be delayed.
For example: In mode 0, the user continuously inputs a large amount of data and switches the mode at the
same time. The mode switching operation is invalid at this time; the module will process all the user data
before performing the new mode detection; so the general recommendation is: Detect the AUX pin output
status, wait for 2ms after the AUX output goes high before switching.
When the module is switched from other modes to sleep mode, if any data has not been processed, the module
will enter the sleep mode after processing the data(including receiving and sending). This feature can be
used for fast sleep mode to save power consumption; for example: the transmitter module works in mode0, the
user initiates serial data "12345",and then does not have to wait for the AUX pin to be idle (high level),and can
directly switch to sleep mode, And the user's main MCU will immediately sleep, the module will automatically

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send all user data through wireless, and automatically enter sleep within 1ms; thus saving the MCU's working
time and reducing power consumption.
Similarly, any mode switch can use this feature. After processing the current mode event, the module will
automatically enter the new mode within 1ms; thereby eliminating the user's query of AUX and achieving the
goal of fast switching ,For example, switching from the transmission mode to the setting mode; the user MCU
can also go to sleep mode in advance before the mode switching, and use the external interrupt function to
obtain the AUX change to perform the mode switching.
This operation mode is very flexible and efficient. It is designed in accordance with the convenience of the
user MCU, and can reduce the workload of the entire system as much as possible, improve system efficiency
and reduce power consumption.
6.2 Transmission mode（Mode0）
Type
When M0 = 0，M1 = 0，module working in module0
transm
ission
The module receives user data from the serial port, the maximum length of the wireless data packet
transmitted by the module is 54 bytes, when the amount of user input data reaches 54 bytes, the
module will start wireless transmission. At this time, the user can continue to enter the data that needs
to be transmitted.
When the user needs to transmit less than 54 bytes, the module waits for about 20ms. If there is no
user data to continue to input, the data is considered to be terminated. At this time, the module sends
all data via wireless.
When the module receives the first user data, AUX outputs low level. When the module puts all data
into the RF chip and starts transmitting, AUX outputs high level.
At this point, it indicates that the last packet of wireless data has been transmitted, and the user can
continue to enter data.
Data packets sent through mode 0 can only be received by the receiving module in mode 0.
receivi
ng
The module is on the wireless receiving function all the time and can receive data packets from mode
0.
After receiving the data packet and the module AUX outputs a low level, it starts sending wireless
data through the serial port TXD pin. After all wireless data is output through the serial port, the
module outputs AUX high level.
6.3 RSSI Mode（Mode1）
Type
When M1= 0，M1 = 0，module working in module1
transmi
ssion
No wireless transmission is allowed, the received serial data will be discarded.

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receivi
ng
Can not receive air wireless data, only scan the signal strength of the current channel, and output a
strength value (relative value) through the serial port every 100ms.
Numerical calculation method: signal strength =-(256 (decimal)-data (decimal)) dBm
If the hexadecimal value output by the serial port is 0x91, the actual signal strength is:-(256
(decimal)-145 (decimal)) =-111dBm
6.4 Setting Mode（Mode2）
Type
When M0 = 0，M1 = 1, module working in module1
transmission
No wireless transmission is allowed, the received serial data will be discarded.
receiving
Unable to receive wireless data
configuration
Can be used for module parameter setting, use serial port 9600, 8N1, set module working
parameters according to specific instruction format
When entering from the setting mode to other modes, the module will reconfigure the
parameters. During the configuration, AUX remains low level;
It outputs a high level after finished, so it is recommended that the user detect the rising edge
of AUX.
6.5 Sleep Mode（Mode3）
Type
When M0 = 1，M1 = 1，module working in module3
transmi
ssion
Unable to transmit wireless data
receivi
ng
Unable to receive wireless data
others
When the module is in the ultra-low power state, all other functions of are turned off, and the sleep
mode can only be exited through the state switch of M1M0.
6.6 Fast communication test
Step
Specific operation
1
Connect E49-900T20S module to the E49-TBL test board, and then plug into the USB test board (E15-USB-T2),
plug into the computer to ensure that the driver has been installed correctly;
Plug in the mode selection jumper cap on the USB test board ( M1 = 0, M0 = 0),

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2
Select 5V (the module supports 2.6 ~ 5.5V).
3
Run the "Serial Debug Assistant" software and select the correct serial port number and observe the sending
window and the corresponding receiving window.
7. Command format
Command mode (Mode 2: M0 = 0, M 1 = 1), the list of supported commands is as follows (when set, only 9600, 8N1
format is supported):
No.
Instruction format
Detailed description
1
C0+operating
parameter
Send C0 + 5 byte working parameters in hexadecimal format, a total of 6 bytes and
must be sent continuously (save when power off)
2
C1+C1+C1
Send three C1s in hexadecimal format. The module returns the saved parameters and
must be sent continuously.

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3
C2+operating
parameter
Send C2 + 5 bytes working parameter in hexadecimal format, a total of 6 bytes and
must be sent continuously(do not save when power off)
4
C3+C3+C3
Send three C3s in hexadecimal format. The module returns version information and
must be sent continuously.
7.1 Default parameters
Model
Factory default parameter value：C0 00 00 19 2E 00
Module type
Frequency
Address
Channel
Air rate
Baud rate
Transmitting power
E49-900T20S
868MHz
0x0000
0x2E
2.4kbps
9600
20
7.2 Reading operating parameter
Instruction format
Detailed description
C1+C1+C1
In the setting mode (M0 = 0, M1 = 1), issue a command to the module
serial port (HEX format): C1 C1 C1,
The module will return the current configuration parameters,
such as: C0 00 00 18 20 00
7.3 Reading version number reading
Instruction format
Detailed description
C3+C3+C3
In the setting mode (M0 = 0, M1 = 1), issue a command to the module serial port
(HEX format): C3 C3 C3,
The module will return the current configuration parameters, such as: C3 49 xx yy;
49 here represents the module model (E49 series), xx is the version number, and yy
refers to other features of the module (users can ignore).
7.4 Parameter setting instruction
No.
Item
Description
Remark

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0
HEAD
Fix 0xC0 or 0xC2, it means this frame data is control
command
Must be 0xC0 or 0xC2
C0: Save the parameters when power-down
C2: Do not save the parameters when
power-down
1
ADDH
High address byte of module
（the default 00H）
00H-FFH
2
ADDL
Low address byte of module
（the default 00H）
00H-FFH
3
SPED
Rate parameters, including serial rate and air rate
7, 6: Serial parity bit
00: 8N1 (default)
01: 8O1
10: 8E1
11: 8N1
-------------------------------------------------
5，4，3 TTL serial speed (bps)
000: Serial baud rate is 1200
001: The serial port baud rate is 2400
010: The serial port baud rate is 4800
011: Serial baud rate is 9600 (default)
100: The serial port baud rate is 19200
101: Serial baud rate is 38400
110: Serial baud rate is 57600
111: Serial baud rate is 115200
-------------------------------------------------
2，1，0 Wireless air rate (bps)
000: The air rate is 1.2k
001: The air speed is 2.4k (default)
010: The air speed is 4.8k
011: The air speed is 9.6k
100: The air speed is 19.2k
101: The air speed is 50k
110: The air speed is 100k
111: 200k air speed
---------------------------------------UART baud
rate can be different between
communication parties
The UART baud rate has nothing to do with
wireless transmission parameters & won’t
affect the wireless transmit / receive
features.

----------------------------------------
----------------------------------------
The lower the air data rate, the longer
the transmitting distance, better
anti-interference performance and
longer transmitting time
The air data rate must keep the same
for both communication parties.
4
CHAN
7,，6，5，4，3，2，1，0 Communication channel
----------------------------------------

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Communication frequency（850M + CHAN * 0.5M）
(Default 0x24: 868M)
00H-A0H，
correspond to 850~930 MHz.
5
OPTION
7; Fixed transmission enabling bit（similar to MODBUS）
0：Transparent transmission mode
1：Fixed transmission mode
-------------------------------------------------
6，5，4，3，2 Reserved bit, write 0
-------------------------------------------------
1, 0 Transmission power (approximation)
00: 20 dBm (default)
01: 17 dBm
10: 14 dBm
11: 10 dBm
In fixed transmission mode, the first
three bytes of each user's data frame
can be used as high/low address and
channel. The module changes its
address and channel when transmit.
And it will revert to original setting
after complete the process.
----------------------------------------
----------------------------------------
The external power must make sure the
ability of current output more than 100mA
and ensure the power supply ripple within
100mV.
Low power transmission is not
recommended due to its low power supply
efficiency.。
For example: The meaning of No.3 "SPED" byte:
The binary bit of the
byte
7
6
5
4
3
2
1
0
Configures by user
0
0
0
1
1
0
0
1
Meaning
UART parity bit 8N1
UART baud rate is 9600
Air data rate is 2.4k
Corresponding
hexadecimal
1
9

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8. Hardware design
It is recommended to use a DC stabilized power supply. The power supply ripple factor is as small as possible, and
the module needs to be reliably grounded.；
Please pay attention to the correct connection of the positive and negative poles of the power supply. Reverse
connection may cause permanent damage to the module；
Please check the power supply to ensure it is within the recommended voltage otherwise when it exceeds the
maximum value the module will be permanently damaged；
Please check the stability of the power supply, the voltage can not be fluctuated frequently；
When designing the power supply circuit for the module, it is often recommended to reserve more than 30% of the
margin, so the whole machine is beneficial for long-term stable operation.；
The module should be as far away as possible from the power supply, transformers, high-frequency wiring and other
parts with large electromagnetic interference.；
High-frequency digital routing, high-frequency analog routing, and power routing must be avoided under the
module. If it is necessary to pass through the module, assume that the module is soldered to the Top Layer, and the
copper is spread on the Top Layer of the module contact part(well grounded), it must be close to the digital part of
the module and routed in the Bottom Layer；
Assuming the module is soldered or placed over the Top Layer, it is wrong to randomly route over the Bottom Layer
or other layers, which will affect the module's spurs and receiving sensitivity to varying degrees；
It is assumed that there are devices with large electromagnetic interference around the module that will greatly
affect the performance. It is recommended to keep them away from the module according to the strength of the
interference. If necessary, appropriate isolation and shielding can be done；
Assume that there are traces with large electromagnetic interference (high-frequency digital, high-frequency analog,
power traces) around the module that will greatly affect the performance of the module. It is recommended to stay
away from the module according to the strength of the interference. If necessary, appropriate isolation and shielding
can be done.
If the communication line uses a 5V level, a 1k-5.1k resistor must be connected in series (not recommended, there is
still a risk of damage)；
Try to stay away from some physical layers such as TTL protocol at 2.4GHz , for example: USB3.0；
The mounting structure of antenna has a great influence on the performance of the module. It is necessary to ensure
that the antenna is exposed, preferably vertically upward. When the module is mounted inside the case, use a good
antenna extension cable to extend the antenna to the outside；
The antenna must not be installed inside the metal case, which will cause the transmission distance to be greatly
weakened.

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9. FAQ
9.1 Communication range is too short
The communication distance will be affected when obstacle exists.
Data lose rate will be affected by temperature, humidity and co-channel interference.
The ground will absorb and reflect wireless radio wave, so the performance will be poor when testing near ground.
Sea water has great ability in absorbing wireless radio wave, so performance will be poor when testing near the sea.
The signal will be affected when the antenna is near metal object or put in a metal case.
Power register was set incorrectly, air data rate is set as too high (the higher the air data rate, the shorter the
distance).
The power supply low voltage under room temperature is lower than recommended value, the lower the voltage, the
lower the transmitting power.
Due to antenna quality or poor matching between antenna and module.
9.2 Module is easy to damage
Please check the power supply to ensure that it is between the recommended power supply voltage. If the maximum
value is exceeded, the module will be permanently damaged.
Please check the stability of power source, the voltage cannot fluctuate too much.
Please make sure anti-static measure are taken when installing and using, high frequency devices have electrostatic
susceptibility.
Please ensure the humidity is within limited range, some parts are sensitive to humidity.
Please avoid using modules under too high or too low temperature.
9.3 BER(Bit Error Rate) is high
There are co-channel signal interference nearby, please be away from interference sources or modify frequency and
channel to avoid interference;
Poor power supply may cause messy code. Make sure that the power supply is reliable.
The extension line and feeder quality are poor or too long, so the bit error rate is high;