XSAT7080 X-Band Transceiver
Revision 0
Remote Control
MN/XSAT7080.IOM
4-2
4.1.2 RS-232
The RS-232 interface is provided at the 19-pin circular J5 connector. The interface provides the
five signals shown in Table 4-2. The XSAT only requires three wires (TD, RD, and Ground), the
other two signal are provided for terminal equipment that requires RTS/CTS handshaking. The
XSAT simply ties these two signals together.
Table 4-2. RS-232 interface
Pin Signal Name I/O
Notes
E
RS-232 RD
Input
XSAT Rx line
G
RS-232 TD
Output
XSAT Tx line
T Ground
Passive
4.2 B
ASIC
P
ROTOCOL
Whether in RS-232 or RS-485 mode, all data is transmitted half-duplex as asynchronous serial
characters suitable for transmission and reception by a UART. In this case, the asynchronous
character format is fixed at; 8 data bits, 1 stop bit, no parity. The baud rate may vary between
1200 baud and 19,200 baud.
All data is transmitted in framed packets. The master is assumed to be a PC or ASCII dumb
terminal, which is controlling the process of monitor and control. The master is the only device
that is permitted to initiate the transmission of data. Slaves are only permitted to transmit when
they have been specifically instructed to do so by the master.
All bytes within a packet are printable ASCII characters. In this context, the Carriage Return and
Line Feed characters are considered printable.
All messages from master to slave require a response (with one exception). This will either be to
return data that has been requested by the master, or to acknowledge reception of an instruction to
change the configuration of the slave. The exception to this is when the master broadcasts a
message (such as Set time/date) using Address 0.
