Warwick X7220 User Manual
Page 7
not then the data is stored in the buffer until the channel becomes free. If it is free then a preamble message will
be transmitted so that the receiving modems can align to the incoming data.
The modem will then transmit a repeater command byte, if set, and a transmitter address byte followed by the
data that has been placed in the buffer memory. The transmission is terminated when a gap of two data bytes is
detected in the incoming data stream.
If more data is sent after a gap of two data bytes then the above sequence will be repeated.
When the receiving modem detects the presence of incoming data it takes CTS (pin 8) low. The repeater
command byte is decoded and the transmitter address compared to the receiver address. If they are the same
or if the global address of 00 is decoded or if the address mode is switched off then the data will be presented at
the serial output port TD (pin 3). At the end of the message CTS is taken high.
If the repeater command is decoded or the repeater mode set in the configuration menu then the data will be
stored and then re-transmitted.
The best results are obtained from the radio modem by setting the transmission speed to the slow setting and
the baud rate to either 4800 or 9600.
5.0 GETTING
STARTED
5.1
Basic Connection on the communication and service ports
TRANSMIT
(TD) ON HOST TO RECEIVE (RD) ON MODEM PIN 2
RECEIVE
(RD)
ON HOST TO TRANSMIT (TD) ON MODEM PIN 3
GROUND
(0V)
ON HOST TO 0V ON MODEM PIN 5
5.2 Power
Connection
240V
ac
5.4
Plug and Play
Connect three wires to the RS232 serial port of the host terminal (0V, TD and RD) as described above.
Connect a 240V power supply to the radio modem.
Configure a PC in Microsoft Windows Hyper Terminal, Procom or any other terminal package with the
following settings:
9600
Baud
No
Parity
1 Stop Bit
Local Echo to OFF
XON/XOFF to OFF
RTS/CTS to OFF (no handshaking)
Connect up a second modem in the same way.
Pressing a key on one PC will transmit the character to the other. Refer to the Section 8.0 Trouble Shooting if
this does not happen.