ICP DAS USA RFU-400 Installation guide

ICP DAS Co., LTD
1
RFU-400 FAQ
Q1、How to increase communication distance of RFU-400? (2016/12/16, Ming)................... 2
Q2、Why some time RFU-400 would receive the data of others channel? (2016/12/16, Ming)
.................................................................................................................................................... 2
Q3、Is there a repeater available for RFU-400 / RFU-433? (2019/11/12, Ming)..................... 3
Q4、Is RFU-400 / RFU-433 possible to communicate with RS-485 device in repeater mode?
(2019/11/12, Ming)..................................................................................................................... 3
Q5、What is the difference between RFU-400 and RFU-433? (2019/11/12, Ming) ................ 3

ICP DAS Co., LTD
2
Q1、How to increase communication distance of RFU-400?
(2016/12/16, Ming)
Ans.：
We provide two ways to reference：
1. Use RF 650 bps baud rate. In the case of a straight line visual distance, the
communication distance of 650 bps baud rate is up to 2 km.
2. Use the following diagram architecture：
Using two RFU-400s, connect their RS-232 or RS-485 to each other, as shown in
the middle of the figure above. So that you can form a group of RFU-400 repeaters to
extend the wireless communication distance.
Q2、Why some time RFU-400 would receive the data of others
channel? (2016/12/16, Ming)
Ans.：
This is because although you use of different channels, but still in each other's
communication bandwidth.
RFU-400 communication bandwidth = 40 k + communication baud rate
Assuming you use a communication rate of 38400 bps, the communication bandwidth is
78.4 kHz, so if the channel spacing is less than 78.4 kHz it is possible to receive data from
each other.
The channel spacing of the RFU-400 in the 429 MHz band is 12.5 kHz, which is
equivalent to an interval of 6 channels. The channel spacing in the 433 MHz band is 100 kHz,
ie, adjacent channels will not be affected.

ICP DAS Co., LTD
3
Q3、Is there a repeater available for RFU-400 / RFU-433? (2019/11/12,
Ming)
Ans.：
Only switch the DIP 7 and 8 (Data Format) of the RFU-400 / RFU-433 to ON and then
power on it. The RFU-400 / RFU-433 module will have repeater function. Please note that,
the repeater function only supports one hop and not supports repeater to repeater.
Q4、Is RFU-400 / RFU-433 possible to communicate with RS-485
device in repeater mode? (2019/11/12, Ming)
Ans.：
The RFU-400 would send repeater message with 2 bytes RSSI value to COM port in
repeater mode. For example, user sends a message 0x01, 0x02, 0x03, 0x04, 0x05, 5 bytes
through a RFU-400 to another. If there is a RFU-400 repeater received this message, the
repeater would send 0x01, 0x02, 0x03, 0x04, 0x05, 0xAA, 0xBB, 7 bytes to COM port, where
the 0xAA is RSSI of transmitter and the 0xBB is RSSI of the repeater. So the repeater mode of
RFU-400 cannot connect with normal RS-485 device. But RFU-433 can enable / disable the
RSSI value through RFU-433 utility, so the repeater mode of RFU-433 can communicate
with RS-485 device.
Q5、What is the difference between RFU-400 and RFU-433?
(2019/11/12, Ming)
Ans.：
Item RFU-400 RFU-433
Frequency Band 429 MHz, 433 MHz 433MHz‘
‘Configure DIP and Rotary switch DIP, Rotary switch and utility
Antenna
connecter SMA RPSMA
RSSI value Fixed at the end of the RF
message in repeater mode Use utility to enable and disable
Output power Default 19 dB (Max) Default 10 dB
(can set by utility)
RF Certification none CE