XDT77 Dual AM/FM Tuner

Appendix A

RS-232 COMMANDS

PURPOSE:

This document describes the RS-232 commands that will operate the XANTECH XDT77 Dual Tuner through the 9-pin RS-232 connector on the rear panel.

General Information:

Data Rate:	19,200 baud
Parity:	None
Word length:	8 data bits, 1 stop bit
Handshake:	No RTS/CTS handshaking
Connections:	simple 3 wire (Rx, Tx, Gnd) interface

DATA ENTRY PROTOCOL:

The serial buss should follow a standard serial communications protocol using Line oriented ASCII data stream. The command line must be followed with a carriage return for the unit to respond. The unit should not echo characters received back to the host.

Command Codes:
Character	Range	Function	Example
X:	0,1	Power Off / On	X1 = Power On, X0 = Power Off
T:	1,2	Tuner #	T1 = Tuner 1, T2 = Tuner 2
B:	1,2	Band #	B1 = AM, Band 2 = FM
P:	00 - 30	Preset #	P01 = Preset 1, P30 = Preset 30, P00 (just for status) = No Preset Selected
F:	4 numbers	Frequency Setting	F0890 = 890 AM, F1045 = 104.5 FM
A:	0,1	Seek Up / Down	A0 = Seek Down, A1 = Seek Up
M:	0,1	Step Up / Down	M0 = Step Down 1 step, M1 = Step Up 1 step
S:	Signal Lock /	1 = locked, 0 = not	S00 (just for status) = no signal, no stereo, S01 = invalid
	Stereo Presence	1 = stereo, 0 = mono	S10 = signal lock (mono), S11 = signal lock (stereo)
Q:	Query status	ask for tuner status	Q1 = Status of Tuner 1, Q2 = Status of Tuner 2
	of tuner		Q3 = Status of both tuners, 1 then 2
N:	0,1	Preset Step Up / Down	N0 = Step Down 1 Preset, N1 = Step Up 1 Preset
L:	01 - 30	Set Preset	L01 = Set Station as Preset #1

Command Examples:

T1B2P01<cr> would command tuner #1 to select band 2 (FM) and tune to FM preset #1

T2B1F1070L03<cr> would command tuner #2 to set AM frequency 1070 kHz as AM preset #3

This command however, would not change the current station tuned on Tuner #2

To select a station to be tuned and THEN set that station as a preset, would require two commands:

T2B1F1070<cr> would command tuner #2 to select band 1 (AM) and tune to frequency 1070 kHz.

T2L03<cr> would command tuner 2 to set the currently tuned station (in this example AM 1070) as AM preset #3

Query Example:

Q1<cr> would solicit the following response:

Feedback as to the status of tuner #1, which would include band select, station preset, frequency tuned, signal lock and stereo presence. The response string would look like this:T1B2P00F1011S11

T1 (tuner 1) B2 (FM), P00 (no preset selected), F1011 (frequency 101.1 MHz), S11 (signal lock & stereo)

Shortcut Commands:

Note: examples below are assuming Tuner 1 is in FM stereo mode and tuned to a station

Command	Response/Action
T1N1<cr>	Tuner 1 would step up to the next higher preset number
T1L01<cr>	Tuner 1 would set the currently tuned station as FM preset #1
T1S10<cr>	Tuner 1 would switch the FM mode to mono
T1M1<cr>	Tuner 1 would step up the frequency 0.2 MHz
T1A0<cr>	Tuner 1 would go into "seek down" mode
T1B1<cr>	Tuner 1 would go to AM mode and tune to the last previously tuned AM station