SiK AT Commands

The RFD900 modem can support the Hayes ‘AT’ modem command set for configuration. The AT command mode can be entered by using the ‘+++’ sequence. When doing this, you have to wait for 1 second before and after entering the command mode in order to prevent data being interpreted as data. When you are successfully in the AT command mode, an ‘OK’ prompt will be displayed on the screen and the RFD900 modem will stop displaying information from the other modem. Whilst in AT mode, you can use the AT commands to control the local RFD900 modem or the RT commands to control the remote modem.

AT Command Description
ATI Shows the radio version
ATI2 Shows the board type
ATI3 Shows board frequency
ATI4 Shows board version
ATI5 Shows all user settable EEPROM parameters
ATI6 Displays TDM timing report
ATI7 Displays RSSI signal report
ATO Exits AT command mode
ATSn? Displays radio parameter number ‘n’
ATSn=X Sets radio parameter number ‘n’ to ‘X’
ATZ Reboots the radio
AT&W Writes current parameters to EEPROM
AT&F Resets all parameters to factory defaults
AT&T=RSSI Enables RSSI debugging report
AT&T=TDM Enables TDM debugging report
AT&T Disables debugging report

The next table that gives a list of RT commands and their description. The x parameter is optional where x is the node ID. For example: use RTI,1 to get RTI value for node 1 or simply use RTI to get the RTI value for the node set in the local NODEDESTINATION.

AT Command Description
RTI[,x] Shows the radio version.
RTI2[,x] Shows the board type
RTI3[,x] Shows board frequency
RTI4[,x] Shows board version
RTI5[,x] Shows all user settable EEPROM parameters
RTI6[,x] Displays TDM timing report
RTI7[,x] Displays RSSI signal report
RTO[,x] Exits AT command mode on the remote node
RTSn? [,x] Displays radio parameter number ‘n’
RTSn=X[,x] Sets radio parameter number ‘n’ to ‘X’
RTZ[,x] Reboots the radio
RT&W[,x] Writes current parameters to EEPROM
RT&F[,x] Resets all parameters to factory defaults
RT&T=RSSI[,x] Enables RSSI debugging report
RT&T=TDM[,x] Enables TDM debugging report
RT&T[,x] Disables debugging report

To set certain registers to a particular value, follow these steps:
1. Use the command ATSn=X where n is the register number and X is the actual value.
2. Use the command AT&W to write the new values to the RFD900 modem.
3. Use the command ATZ to reboot the RFD900 modem.

S Reg # S Register Description Default Val Max Val Min Val Should be the same at both ends of the link for successful communication ?
0 FORMAT This is for EEPROM version, it should not be changed Firmware dependant N/A N/A No
1 SERIAL_SPEED Serial speed in ‘one byte form’ 57 115 2 No
2 AIR_SPEED Air data rate in one byte form 64, 1281 250 2 Yes
3 NETID Network ID. 25 499 0 Yes
4 TXPOWER Transmit power in dBm. Maximum is 30dBm 20, 271 30 0 No
5 ECC3 Enables or disables the golay error correcting code 1, 01 1 0 Yes
6 MAVLINK4 Enables or disables the MAVLink framing and reporting 1, 01 1 0 No
7 OP_RESEND5 Opportunic Resend 1, 01 1 0 No
8 MIN_FREQ Min freq in KHz 915,000 927,000 902,000 Yes
9 MAX_FREQ Max freq in KHz 928,000 928,000 903,000 Yes
10 NUM_CHANNELS Number of frequency hopping channels 50, 201 50 5 Yes
11 DUTY_CYCLE The percentage of time to allow transmit 100 100 10 No
12 LBT_RSSI Listen before talk threshold 0 1 0 Yes
13 MANCHESTER Manchester encoding 0 1 0 Yes
14 RTSCTS Ready To Send and Clear To Send 0 1 0 No
15 NODEID2 Node ID. Base node ID is 0. One node must be acting as a base for a multipoint environment to work. NODECOUNT must be updated first before updating this parameter with bigger number. 21 29 0 N/A
16 NODEDESTINATION2 Remote node ID to communicate with.
Set the value to 65535 to broadcast to all nodes. Cannot be the same as NODEID. NODECOUNT must be updated first before updating this parameter with bigger number.
655351 29 0 No
17 SYNCANY2 If set to 1, allows the modem to send data to all non-base nodes without finding the base. It is strongly recommended to set the value to 0 to avoid unwanted data communication confusion on a multipoint environment. 01 1 0 No
18 NODECOUNT2 The total number of nodes. 31 30 2 Yes


1Defaults for firmware version 2.* and later
2Available only for firmware version 2.* and later
3ECC – Software Detection and correction, extra packet information (twice the packet length) is sent to allow the recovery of corrupted packets.
4Injects RSSI packet when Mavlink protocol used and heartbeat packet detected.
5Opportunistic resend allows the node to resend packets if it has spare bandwidth.