CDR-3250/80 TECHNICAL MANUAL
Issue 2.2 3-47
|STX|1 2 3|F 2 3 9 8 7 6 0 0 0 SP M C|CR|
| | | / | |
|---|-Adr-|--------Data Field-/------|--|
/ / \
Start ASCII Carriage
of Text Space Character Return
NOTES:
The first character of a transmission will always be STX (start of text, ASCII code 02).
The second, third, and fourth characters will contain the address in decimal, with the most significant digit first, of the
receiver sending the transmission or to which it is being sent by the controller. The address code for any receiver may
be any number from 000 to 254 provided that it is not used by any other unit connected to the bus. Address 255 is
reserved for "broadcasting" to all receivers on the bus (refer to paragraph 3.8.6). The controller has no address. All three
digits must be transmitted. Addresses less than 100 must be filled with '0' digits on the left. The address is set from the
front panel with the soft key sequence CONFIG6 REMOTE6 ADDRS.
The fifth character of the transmission is the beginning of the data field. This field may contain as few as one or as many
as 250 characters. The data field may contain one or more messages. If more than one message is contained in the data
field, each message must be separated from the next by one or more blank (space) characters.
Any number of messages may be included in the data field provided that the maximum number of characters is not
exceeded. There are, however, certain request for status commands that may not be mixed with any other request for
status commands in the same transmission. These messages will be noted as such in table 3-5.
The final character of the transmission will be a CR (carriage return). This character will follow the last character of the
data field.
This transmission above from the controller is addressed to the receiver with address 123 and contains two messages:
"F23987600" and "MC".
When sending messages to the receiver that require numeric values as arguments, it is not necessary to include leading
zeros. For example, to send a message to change the frequency to 5.67 MHz, the command message "F5670000" may be
given in place of "F05670000". When a request for a status message is made, the reply will always include any leading
zeros so that the value may be extracted by counting characters in the message.
Figure 3-9 Serial Bus Message Format.
|ST|D1 D2 D3 D4 D5 D6 D7 (D8)|(P)|S (S)|
| | | | |
|--|--------Data Bits--------|---|-----|
/ / \
Start Parity Stop
Bit Bit Bit(s)
NOTES: Information is passed in full duplex as characters in an asynchronous serial format. Each character consists of a start
bit, 7 or 8 data bits with the least significant bit sent first, an optional parity bit which may provide odd or even parity,
and one or two stop bits. The serial transmission rate may be set to each of the following standard rates: 75, 110, 150,
300, 600, 1200, 2400, 4800, 9600, 19200, 38400, and 125000 bits per second. Number of data bits, number of stop bits,
parity options and baud rate are all selectable from the front panel of the receiver through the keypad from the CONFIG
6 REMOTE menu. The selected values take effect immediately when changed and are stored in non-volatile memory.
Figure 3-10 Serial Bus Character Format.
Courtesy of http://BlackRadios.terryo.org
To Next Page
Loading...