diff --git a/Source/Apps/Tune/Tune.asm b/Source/Apps/Tune/Tune.asm
index aa28cb95..1b523d3c 100644
--- a/Source/Apps/Tune/Tune.asm
+++ b/Source/Apps/Tune/Tune.asm
@@ -1998,11 +1998,11 @@ PLAYVIAHBIOS:
 	LD	L, A
 	RST	08
 
-	LD	B, BF_SNDPIT
+	LD	B, BF_SNDPRD
 	LD	C, 0
 	LD	HL, (AYREGS+TonA)
 	ld	a, h
-	AND	$3F
+	AND	$0F
 	LD	H, A
 	RST	08
 
@@ -2023,11 +2023,11 @@ PLAYVIAHBIOS:
 	LD	L, A
 	RST	08
 
-	LD	B, BF_SNDPIT
+	LD	B, BF_SNDPRD
 	LD	C, 0
 	LD	HL, (AYREGS+TonB)
 	ld	a, h
-	AND	$3F
+	AND	$0F
 	LD	H, A
 	RST	08
 
@@ -2048,11 +2048,11 @@ PLAYVIAHBIOS:
 	LD	L, A
 	RST	08
 
-	LD	B, BF_SNDPIT
+	LD	B, BF_SNDPRD
 	LD	C, 0
 	LD	HL, (AYREGS+TonC)
 	ld	a, h
-	AND	$3F
+	AND	$0F
 	LD	H, A
 	RST	08
 
diff --git a/Source/Apps/Tune/hbios.inc b/Source/Apps/Tune/hbios.inc
index 874a9699..f2442f78 100644
--- a/Source/Apps/Tune/hbios.inc
+++ b/Source/Apps/Tune/hbios.inc
@@ -10,6 +10,6 @@ BF_SYSGET	.EQU	$F8		; HBIOS: SYSGET function
 BF_SND		.EQU	$50
 BF_SNDRESET	.EQU	BF_SND + 0	; RESET SOUND SYSTEM
 BF_SNDVOL	.EQU	BF_SND + 1	; REQUEST SOUND VOL - D IS CHANNEL, E CONTAINS VOLUME (255 MAX, 0 SILENT) - SCALED AS REQUIRED BY DRIVER (EG: MAPS TO JUST 4 BIT RESOLUTION FOR SN76489)
-BF_SNDPIT	.EQU	BF_SND + 2	; REQUEST SOUND PITCH - D IS CHANNEL, HL CONTAINS PITCH (0 LOWEST NOTE, FFFF HIGHEST NOTE) - SCALED BY DRIVER (EG: MAPS TO JUST 10 BITS FOR SN76489 )
+BF_SNDPRD	.EQU	BF_SND + 2	; REQUEST SOUND PERIOD - D IS CHANNEL, HL CONTAINS PERIOD (0 LOWEST NOTE) - SCALED BY DRIVER (EG: MAPS TO JUST 10 BITS FOR SN76489 )
 BF_SNDPLAY	.EQU	BF_SND + 4	; INITIATE THE REQUESTED SOUND COMMAND
 BF_SNDQUERY	.EQU	BF_SND + 5	; D IS CHANNEL, E IS SUBCOMMAND
diff --git a/Source/Doc/Architecture.md b/Source/Doc/Architecture.md
index 94c9a85d..c618667e 100644
--- a/Source/Doc/Architecture.md
+++ b/Source/Doc/Architecture.md
@@ -1324,17 +1324,20 @@ Note that not all sounds chips implement 256 volume levels.  The
 driver will scale the volume to the closest possible level the
 chip provides.
 
-### Function 0x52 -- Sound Pitch (SNDPIT)
+### Function 0x52 -- Sound period (SNDPRD)
 
 | _Entry Parameters_
 |       B: 0x52
 |       C: Audio Device Unit ID
-|       HL: Pitch (0000=lowest note, FFFF=highest note)
+|       HL: period (0000=lowest note, FFFF=highest note)
 
-This function sets the sound chip pitch parameter.  The pitch will
+|      _Returned Values_
+|           A: Status (0=OK, else error)
+
+This function sets the sound chip period parameter.  The period will
 be applied when the next SNDPLAY function is invoked.
 
-The pitch value is a driver specific value.  To play standardized
+The period value is a driver specific value.  To play standardized
 notes, use the SNDNOTE function.
 
 ### Function 0x53 -- Sound Note (SNDNOTE)
@@ -1344,14 +1347,17 @@ notes, use the SNDNOTE function.
 |       C: Audio Device Unit ID
 |       L: Note (0 to 255 quarter notes)
 
-This function sets the sound chip pitch parameter according to
+|      _Returned Values_
+|           A: Status (0=OK, else error)
+
+This function sets the sound chip period parameter according to
 standardized notes.
 
-The value corresponds to standard musical notes.  The value allows 
-for selection of a quarter of a semitone by giving a value between 0 
+The value corresponds to standard musical notes.  The value allows
+for selection of a quarter of a semitone by giving a value between 0
 and up to the drivers maximum supported value. The lowest note is (0).
 
-For the SN76490 chip, 0 corresponds to note A1# and the value 249 is 
+For the SN76490 chip, 0 corresponds to note A1# and the value 249 is
 the maximum supported value, and it corresponds to note C7.
 
 ### Function 0x54 -- Sound Play (SNDPLAY)
@@ -1359,9 +1365,12 @@ the maximum supported value, and it corresponds to note C7.
 | _Entry Parameters_
 |       B: 0x54
 |       C: Audio Device Unit ID
-|       D: Channel
+|       E: Channel
 
-This function applies the previously specified volume and pitch by
+|      _Returned Values_
+|           A: Status (0=OK, else error)
+
+This function applies the previously specified volume and period by
 programming the sound chip with the appropriate values.  The values
 are applied to the specified channel of the chip.
 
@@ -1374,6 +1383,81 @@ HBIOS B=53 C=00 L=69      ; Select Middle C (C4) assuming SN76489
 HBIOS B=54 C=00 D=01      ; Play note on Channel 1
 ```
 
+### Function 0x55 -- Sound Play (SNDQUERY)
+
+| _Entry Parameters_
+|       B: 0x54
+|       C: Audio Device Unit ID
+|       E: Subfunction
+
+|      _Returned Values_
+|           A: Status (0=OK, else error)
+
+This function will return the status of current pending command or
+key aspects of the specific Audio Device.
+
+#### SNDQUERY Subfunction 0x01 -- Get count of audio channels supported (SNDQ_CHCNT)
+
+|      _Entry Parameters_
+|           B: 0x54
+|           E: 0x01
+
+|      _Returned Values_
+|           A: Status (0=OK, else error)
+|           B: Count of standard tone channels
+|           C: Count of noise tone channels
+
+#### SNDQUERY Subfunction 0x01 -- Get current volume setting (SNDQ_VOL)
+
+|      _Entry Parameters_
+|           B: 0x54
+|           E: 0x02
+
+|      _Returned Values_
+|           A: Status (0=OK, else error)
+|           H: 0
+|           L: Current volume setting
+
+#### SNDQUERY Subfunction 0x03 -- Get current period setting (SNDQ_PERIOD)
+
+|      _Entry Parameters_
+|           B: 0x54
+|           E: 0x03
+
+|      _Returned Values_
+|           A: Status (0=OK, else error)
+|           HL: Current period setting
+
+#### SNDQUERY Subfunction 0x04 -- Get device details (SNDQ_DEV)
+
+|      _Entry Parameters_
+|           B: 0x54
+|           E: 0x04
+
+|      _Returned Values_
+|           A: Status (0=OK, else error)
+|           B: Driver identity
+|           HL: Driver specific port settings
+|           DE: Driver specific port settings
+
+Reports information about the audio device unit specified.
+
+At this stage, only one driver type is supported (SN76489), but is
+envisage that more will be added in the future.
+
+Register B reports the audio device type (see below).
+
+Registers HL and DE contain relevant port address for the hardware
+as such are specific to each device type.
+
+The currently defined audio device types are:
+
+AUDIO ID       | Value | Device     | Returned registers
+-------------- | ----- | ---------- | --------------------------------------------
+SND_SN76489    | 0x01  | SN76489    | E: Left channel port, L: Right channel port
+SND_SNAY38910  | 0x02  | AY-3-8910  | D: Address port, E: Data port
+
+
 `\clearpage`{=latex}
 
 System (SYS)
diff --git a/Source/HBIOS/hbios.inc b/Source/HBIOS/hbios.inc
index 17a9ae23..e3fe6667 100644
--- a/Source/HBIOS/hbios.inc
+++ b/Source/HBIOS/hbios.inc
@@ -55,16 +55,22 @@ BF_VDAKRD	.EQU	BF_VDA + 14	; READ KEYBOARD
 BF_SND		.EQU	$50
 BF_SNDRESET	.EQU	BF_SND + 0	; RESET SOUND SYSTEM
 BF_SNDVOL	.EQU	BF_SND + 1	; REQUEST SOUND VOL - L CONTAINS VOLUME (255 MAX, 0 SILENT) - SCALED AS REQUIRED BY DRIVER (EG: MAPS TO JUST 4 BIT RESOLUTION FOR SN76489)
-BF_SNDPIT	.EQU	BF_SND + 2	; REQUEST SOUND PITCH - HL CONTAINS PITCH DRIVER SPECIFIC VALUE
+BF_SNDPRD	.EQU	BF_SND + 2	; REQUEST SOUND PERIOD - HL CONTAINS DRIVER SPECIFIC VALUE
 BF_SNDNOTE	.EQU	BF_SND + 3	; REQUEST NOTE - L CONTAINS NOTE - EACH VALUE IS QUARTER NOTE
 BF_SNDPLAY	.EQU	BF_SND + 4	; INITIATE THE REQUESTED SOUND COMMAND
-BF_SNDQUERY	.EQU	BF_SND + 5	; D IS CHANNEL, E IS SUBCOMMAND
+BF_SNDQUERY	.EQU	BF_SND + 5	; E IS SUBFUNCTION
 ;
 ; BF_SNDQUERY SUBCOMMANDS
 BF_SNDQ_STATUS		.EQU	0
 BF_SNDQ_CHCNT		.EQU	BF_SNDQ_STATUS + 1	; RETURN COUNT OF CHANNELS
-BF_SNDQ_SVOLUME		.EQU	BF_SNDQ_STATUS + 2	; 8 BIT NUMBER
-BF_SNDQ_SPITCH		.EQU	BF_SNDQ_STATUS + 3	; 16 BIT NUMBER
+BF_SNDQ_VOLUME		.EQU	BF_SNDQ_STATUS + 2	; 8 BIT NUMBER
+BF_SNDQ_PERIOD		.EQU	BF_SNDQ_STATUS + 3	; 16 BIT NUMBER
+BF_SNDQ_DEV		.EQU	BF_SNDQ_STATUS + 4	; RETURN DEVICE TYPE CODE AND IO PORTS - TYPE IN B, PORTS IN DE, HL
+
+BF_SNDDEV		.EQU	0			; TYPES OF SOUND DRIVERS
+BF_SND_SN76489		.EQU	BF_SNDDEV + 1
+BF_SND_SNAY38910	.EQU	BF_SNDDEV + 2
+
 ;
 BF_SYS		.EQU	$F0
 BF_SYSRESET	.EQU	BF_SYS + 0	; SOFT RESET HBIOS
diff --git a/Source/HBIOS/sn76489.asm b/Source/HBIOS/sn76489.asm
index 3c12acb6..4ce9546b 100644
--- a/Source/HBIOS/sn76489.asm
+++ b/Source/HBIOS/sn76489.asm
@@ -33,9 +33,9 @@ SN7_LAST_NOTE	.EQU	209300		; C7
 A1S		.EQU	SN7RATIO / SN7_FIRST_NOTE
 C7		.EQU	SN7RATIO / SN7_LAST_NOTE
 
-       .ECHO "SN76489: range of A1# (pitch: "
+       .ECHO "SN76489: range of A1# (period: "
        .ECHO A1S
-       .ECHO ") to C7 (pitch: "
+       .ECHO ") to C7 (period: "
        .ECHO C7
        .ECHO ")\n"
 
@@ -132,48 +132,78 @@ SN7_NOTE:
 	LD	HL, SN7NOTETBL
 	ADD	HL, DE
 
-	LD	A, (HL)			; RETRIEVE PITCH COUNT FROM SN7NOTETBL
+	LD	A, (HL)			; RETRIEVE PERIOD COUNT FROM SN7NOTETBL
 	INC	HL
 	LD	H, (HL)
 	LD	L, A
 
-	JR	SN7_PITCH		; APPLY PITCH
+	JR	SN7_PERIOD		; APPLY PERIOD
 
 SN7_NOTE1:
 	OR	$FF			; NOT IMPLEMENTED YET
 	RET
 
-SN7_PITCH:
-	AUDDEBUG("SN7PIT ")
+SN7_PERIOD:
+	AUDDEBUG("SN7PRD ")
 	AUDTRACE_HL
 	AUDDEBUG("\r\n")
-	LD	(PENDING_PITCH), HL
 
+	LD	A, H
+	CP	$04
+	JP	NC, SN7_QUERY_PERIOD1	; RETURN NZ IF NUMBER TOO LARGE
+
+	LD	(PENDING_PERIOD), HL
 	XOR	A			; SIGNAL SUCCESS
 	RET
 
+SN7_QUERY_PERIOD1:			; REQUESTED PERIOD IS LARGER THAN THE SN76489 CAN SUPPORT
+	LD	L, $FF
+	LD	H, $FF
+	LD	(PENDING_PERIOD), HL
+
+	OR	$FF			; SIGNAL FAILURE
+	RET
+
 SN7_PLAY:
 	AUDDEBUG("SN7PLY ")
 	AUDTRACE_D
 	AUDDEBUG("\r\n")
 
+	LD	A, (PENDING_PERIOD + 1)
+	CP	$FF
+	JR	Z, SN7_PLAY1		; PERIOD IS TOO LARGE, UNABLE TO PLAY
 	CALL	SN7_APPLY_VOL
-	CALL	SN7_APPLY_PIT
+	CALL	SN7_APPLY_PRD
 
 	XOR	A			; SIGNAL SUCCESS
 	RET
 
+SN7_PLAY1:				; TURN CHANNEL VOL TO OFF AND STOP PLAYING
+	LD	A, (PENDING_VOLUME)
+	PUSH	AF
+	LD	A, 0
+	LD	(PENDING_VOLUME), A
+	CALL	SN7_APPLY_VOL
+	POP	AF
+	LD	(PENDING_VOLUME), A
+
+	OR	$FF			; SIGNAL FAILURE
+	RET
+
 SN7_QUERY:
 	LD	A, E
 	CP	BF_SNDQ_CHCNT
 	JR	Z, SN7_QUERY_CHCNT
 
-	CP	BF_SNDQ_SPITCH
-	JR	Z, SN7_QUERY_PITCH
+	CP	BF_SNDQ_PERIOD
+	JR	Z, SN7_QUERY_PERIOD
 
-	CP	BF_SNDQ_SVOLUME
+	CP	BF_SNDQ_VOLUME
 	JR	Z, SN7_QUERY_VOLUME
 
+	CP	BF_SNDQ_DEV
+	JR	Z, SN7_QUERY_DEV
+
 	OR	$FF			; SIGNAL FAILURE
 	RET
 
@@ -183,9 +213,8 @@ SN7_QUERY_CHCNT:
 	XOR	A
 	RET
 
-SN7_QUERY_PITCH:
-	LD	HL, (PENDING_PITCH)
-
+SN7_QUERY_PERIOD:
+	LD	HL, (PENDING_PERIOD)
 	XOR	A
 	RET
 
@@ -197,6 +226,14 @@ SN7_QUERY_VOLUME:
 	XOR	A
 	RET
 
+SN7_QUERY_DEV:
+
+	LD	B, BF_SND_SN76489
+	LD	DE, SN76489_PORT_LEFT 	; E WITH LEFT PORT
+	LD	HL, SN76489_PORT_RIGHT	; L WITH RIGHT PORT
+
+	XOR	A
+	RET
 ;
 ;	UTIL FUNCTIONS
 ;
@@ -238,11 +275,11 @@ SN7_APPLY_VOL:				; APPLY VOLUME TO BOTH LEFT AND RIGHT CHANNELS
 	POP	BC
 	RET
 
-SN7_APPLY_PIT:
+SN7_APPLY_PRD:
 	PUSH	DE
 	PUSH	BC
 	PUSH	AF
-	LD	HL, (PENDING_PITCH)
+	LD	HL, (PENDING_PERIOD)
 
 	LD	A, D
 	AND	$3
@@ -252,11 +289,11 @@ SN7_APPLY_PIT:
 	RLCA
 	RLCA
 	OR	$80
-	LD	B, A			; PITCH COMMAND 1 - CONTAINS CHANNEL ONLY
+	LD	B, A			; PERIOD COMMAND 1 - CONTAINS CHANNEL ONLY
 
 	LD	A, L			; GET LOWER 4 BITS FOR COMMAND 1
 	AND	$F
-	OR	B			; A NOW CONATINS FIRST PITCH COMMAND
+	OR	B			; A NOW CONATINS FIRST PERIOD COMMAND
 
 	AUDTRACE(TRACE_PORT_WR)
 	AUDTRACE_A
@@ -279,7 +316,7 @@ SN7_APPLY_PIT:
 	RLCA
 	RLCA
 	RLCA				; AND PLACE IN BITS 5 AND 6
-	OR	B			; OR THE TWO SETS OF BITS TO MAKE 2ND PITCH COMMAND
+	OR	B			; OR THE TWO SETS OF BITS TO MAKE 2ND PERIOD COMMAND
 
 	AUDTRACE(TRACE_PORT_WR)
 	AUDTRACE_A
@@ -297,7 +334,7 @@ SN7_APPLY_PIT:
 SN7_FNTBL:
 	.DW	SN7_RESET
 	.DW	SN7_VOLUME
-	.DW	SN7_PITCH
+	.DW	SN7_PERIOD
 	.DW	SN7_NOTE
 	.DW	SN7_PLAY
 	.DW	SN7_QUERY
@@ -307,8 +344,8 @@ SN7_FNTBL:
 	!!!!!
 #ENDIF
 
-PENDING_PITCH
-	.DW	0		; PENDING PITCH (10 BITS)
+PENDING_PERIOD
+	.DW	0		; PENDING PERIOD (10 BITS)
 PENDING_VOLUME
 	.DB	0		; PENDING VOL (8 BITS -> DOWNOVERTED TO 4 BITS AND INVERTED)
 
@@ -322,8 +359,8 @@ TRACE_VOLUME_SET	.DB	"\r\nSN7_VOLUME_SET CH: $"
 TRACE_PLAY		.DB	"\r\nPLAY\r\n$"
 TRACE_VOLUME		.DB	", VOL: $"
 TRACE_PORT_WR		.DB	"\r\nOUT SN76489, $"
-TRACE_PITCH_SET		.DB	"\r\nSN7_PITCH_SET CH: $"
-TRACE_PITCH		.DB	", PITCH: $"
+TRACE_PERIOD_SET		.DB	"\r\nSN7_PERIOD_SET CH: $"
+TRACE_PERIOD		.DB	", PERIOD: $"
 TRACE_NEWLINE		.DB	"\r\n$"
 #ENDIF
 
diff --git a/Source/HBIOS/util.asm b/Source/HBIOS/util.asm
index a1ca84ff..8dc066db 100644
--- a/Source/HBIOS/util.asm
+++ b/Source/HBIOS/util.asm
@@ -187,9 +187,9 @@ PRTHEXWORD:
 ;
 PRTHEXWORDHL:
 	PUSH	AF
-	LD	A,D
+	LD	A,H
 	CALL	PRTHEXBYTE
-	LD	A,E
+	LD	A,L
 	CALL	PRTHEXBYTE
 	POP	AF
 	RET