Pin description of TX1M/RX1M with Modem mode selected
The 'modem' mentioned is a 1200 baud RS232 semi-intelligent unit (Transmitter is enabled when valid
serial data is present, so no separate Transmit Enable control is needed. Coding in the data stream also
permits the receiver to ignore noise and only output valid serial data.
Pin Description – TX1M
Pin
1
Name
0V
Function
Ground
2
3
TXE
N/C
Must be tied to 0V
4
N/C
5
6
7
+4.4Vout
PGM
0V
DC supply. 75mA maximum drain. Only present when TXE is low
Serial programming/configuration input at RS232 level
Ground
8
9
MOD TXD (P1) Serial data input at RS232 level
MOD N/C (P2)
10
MOD TXH (P3) Active Low Transmit Hold for continuous transmission (useful for test)
Pin Description – RX1M
Pin
Name
Function
1
RSSI
DC level between 0.5V and 2.5V. 60dB dynamic range
(only valid during databursts)
2
N/C
3
N/C
(modem tones or noise present)
4
N/C
(modem tones or noise present)
5
6
+4.4V out
0V
DC supply. 75mA maximum drain. Present if unit is powered
Ground
7
PGM
Serial programming/configuration input at RS232 level
8
MOD N/C (P1)
9
MOD RXD (P2) Modem Received Data at TTL level (requires RS232 driver)
10
MOD CDE (P3) Pull low to enable Carrier Detect on modem operation (not recommended)
Both the TX1M and the RX1M should be configured to required operating frequency using GOCHAN
command before starting to use the internal 1200 baud modem, because the P1-P3 pins will be used as
Modem Data pins and the modem will operate on the last serially selected channel after SETMOD
command is used to enable the Modem.
Antenna
Antenna
0V (C1)
NC (C2)
TXE (C2)
TX1M
PC serial port
PC serial port
+4.4V out (C5)
GND (C6)
4.4V 0ut (C5)
PGM (C6)
1
2
2400bps
1200bps
1
6
2
6
SW1
RX1M
GND(C7)
RXD
PGM (C7)
2400bps
7
8
9
3
7
8
9
3
TXD
100kΩ
TXD
SGD
MOD TXD
MOD RXD (C9)
uC
UART
1200bps
4
100k
Ω
(C8)
4
5
VDD
µC
MAX232
SGD
5
NPN
UART
4.5 - 15V
4.5 - 15V
Figure 5: TX1M and RX1M interfaced to PC serial port in modem mode
Note: Baud rate used for Modem is half that of used for serial configuration. Attached RS232
devices should be set with the following: 1200bps, 8 Data bits, No Parity, 1/2 stop bits, no flow
control
For TX1M, TXD (Pin 3) of a Serial Port can be switched from PGM (Pin C6) to MOD TXD (Pin C8) with
no RS232 driver in between. However, in RX1M, MOD RXD (Pin C9) requires an RS232 line driver
before it can be connected to RXD (pin 2) of a serial port. Some of the RS232 line drivers can be powered
from the regulated +4.4V out (Pin C5).
Radiometrix Ltd
TX1M/RX1M Data Sheet
page 6
RADIOMETRIX [ RADIOMETRIX LTD ]
