RM24100D operating manual Page 3
1.1 RS485/RS422 Communications (RS485/RS422 Models only)
The RS485/RS422 protocol allows for a wired connection to be established as far as 4000ft (1200m). RS232 only allows
for a wired connection up to 100ft (30.5m). The RM24100D includes an on-board termination resistor which can be
selected by linking J1 on the main PCB inside the unit. The termination resistor is 120 Ohms.
1.2 RSSI (Received Signal Strength Indicator) Red LEDS
3 LED’s on: Very strong signal (>30db fade margin)
2 LED’s on: Strong Signal (>20db fade margin)
1 LED on:
Moderate Signal (>10db fade margin)
0 LED’s on: Weak Signal (<10db fade margin)
1.3 Minimum connection required for the RM24100D
Power (ALL models)
: (8->30V DC), Ground
RS232
: TXD,RXD, Ground
RS485
: D+ (B), D- (A)
RS422
: TXD+ (B), TXD- (A), RXD+ (B), RXD- (A)
2 Network Setup
2.1 Frequency Channel Selection
The RM24100D allows for IEEE 802.15.4 channel assignment which ranges from 2407.5 to 2467.5 MHz with 5MHz
spacing between channels. The most likely cause of interference for the RM24100D will be from a wireless LAN (802.11b/
g access points). If interference is detected then the RM24100D can be configured to use another channel as in the list
below. By default the RM24100D is shipped with the settings of channel 12 (0x0c). The RM24100D can handle 12
channels with 65535 modems per channel.
Center Frequency (MHz)
Nominal Occupied bandwidth
Channel
2410
2407.5-2412.5
12 (0x0c)
2415
2412.5-2417.5
13 (0x0d)
2420
2417.5-2422.5
14 (0x0e)
2425
2422.5-2427.5
15 (0x0f)
2430
2427.5-2432.5
16 (0x10)
2435
2432.5-2437.5
17 (0x11)
2440
2437.5-2442.5
18 (0x12)
2445
2442.5-2447.5
19 (0x13)
2450
2447.5-2452.5
20 (0x14)
2455
2452.5-2457.5
21 (0x15)
2460
2457.5-2462.5
22 (0x16)
2465
2462.5-2467.5
23 (0x17)
2.2 Network configuration
The RM24100100D can be operated in a unicast or broadcast mode.
Unicast Mode (Default):
Unicast mode is the only mode that supports retries. While in this mode, receiving modules
send an ACK (acknowledge) of RF packet reception to the transmitter. If the transmitter does not receive an ACK, it will
try to resend the packet up to 3 times. For 2 modems to communicate with each other, the destination address of the
transmitter module must match the address of the receiver.
