AI4AVSummary
Parasound Halo C 2 and C 1 surround controllers with RS-232C serial control. Binary protocol at 9600 baud with fixed RS-Enable preamble required before every command. Covers power, volume, source selection, surround modes, tone/speaker trim, zone control, tape monitoring, setup menu navigation, and full status query with unsolicited feedback.
Transport
protocols:
- serial
serial:
baud_rate: 9600
data_bits: 8
parity: none
stop_bits: 1
flow_control: none
pinout:
txd: 2
rxd: 3
gnd: 5
cable: "DB9 straight-through (NOT null modem)"
auth:
type: none # inferred: no auth procedure in source
Traits
traits:
- powerable # inferred: power on/off/toggle commands
- queryable # inferred: full status report query + unsolicited feedback
- levelable # inferred: volume, bass, treble, trim controls
- routable # inferred: source selection commands
Preamble
preamble:
description: "RS Enable command must precede every command (except full status query)"
decimal: [224, 82, 83, 33]
hex: [0xE0, 0x52, 0x53, 0x21]
note: "No carriage returns required. No spaces/line feeds between bytes."
Actions
actions:
# Power Control
- id: power_off
label: Power Off (Standby)
kind: action
params: []
decimal: [34]
hex: [0x22]
- id: power_on
label: Power On
kind: action
params: []
decimal: [35]
hex: [0x23]
- id: power_toggle
label: Power Toggle
kind: action
params: []
decimal: [6]
hex: [0x06]
# Volume Control
- id: volume_plus
label: Volume Plus
kind: action
params: []
decimal: [53]
hex: [0x35]
- id: volume_minus
label: Volume Minus
kind: action
params: []
decimal: [54]
hex: [0x36]
- id: mute_toggle
label: Mute Toggle
kind: action
params: []
decimal: [7]
hex: [0x07]
- id: mute_on
label: Mute On
kind: action
params: []
decimal: [32]
hex: [0x20]
- id: mute_off
label: Mute Off
kind: action
params: []
decimal: [33]
hex: [0x21]
# Source Selection
- id: source_plus
label: Source Plus
kind: action
params: []
decimal: [8]
hex: [0x08]
- id: source_minus
label: Source Minus
kind: action
params: []
decimal: [9]
hex: [0x09]
- id: source_video_1
label: Source Video 1
kind: action
params: []
decimal: [13]
hex: [0x0D]
- id: source_video_2
label: Source Video 2
kind: action
params: []
decimal: [14]
hex: [0x0E]
- id: source_video_3
label: Source Video 3
kind: action
params: []
decimal: [15]
hex: [0x0F]
- id: source_video_4
label: Source Video 4
kind: action
params: []
decimal: [16]
hex: [0x10]
- id: source_video_5
label: Source Video 5
kind: action
params: []
decimal: [17]
hex: [0x11]
- id: source_video_6
label: Source Video 6
kind: action
params: []
decimal: [18]
hex: [0x12]
- id: source_audio_1
label: Source Audio 1
kind: action
params: []
decimal: [19]
hex: [0x13]
- id: source_audio_2
label: Source Audio 2
kind: action
params: []
decimal: [20]
hex: [0x14]
- id: source_audio_3
label: Source Audio 3
kind: action
params: []
decimal: [72]
hex: [0x48]
- id: source_audio_4
label: Source Audio 4
kind: action
params: []
decimal: [73]
hex: [0x49]
- id: source_analog_71
label: Source Analog 7.1
kind: action
params: []
decimal: [100]
hex: [0x64]
- id: source_analog_71_toggle
label: Source Analog 7.1 Toggle
kind: action
params: []
decimal: [136]
hex: [0x88]
- id: source_auto_search
label: Active Source Auto Search
kind: action
params: []
decimal: [144]
hex: [0x90]
# Surround Mode Selection
- id: surround_minus
label: Surround Mode Minus
kind: action
params: []
decimal: [10]
hex: [0x0A]
- id: surround_plus
label: Surround Mode Plus
kind: action
params: []
decimal: [11]
hex: [0x0B]
- id: surround_mono
label: Mono
kind: action
params: []
decimal: [42]
hex: [0x2A]
- id: surround_stereo
label: Stereo
kind: action
params: []
decimal: [43]
hex: [0x2B]
- id: surround_prologic
label: Prologic
kind: action
params: []
decimal: [44]
hex: [0x2C]
- id: surround_natural
label: Natural
kind: action
params: []
decimal: [45]
hex: [0x2D]
- id: surround_party
label: Party
kind: action
params: []
decimal: [46]
hex: [0x2E]
- id: surround_club
label: Club
kind: action
params: []
decimal: [47]
hex: [0x2F]
- id: surround_concert
label: Concert
kind: action
params: []
decimal: [48]
hex: [0x30]
- id: surround_plii_movie
label: Prologic II/IIx Movie
kind: action
params: []
decimal: [160]
hex: [0xA0]
- id: surround_plii_music
label: Prologic II/IIx Music
kind: action
params: []
decimal: [161]
hex: [0xA1]
- id: surround_neo6_cinema
label: DTS Neo6 Cinema
kind: action
params: []
decimal: [162]
hex: [0xA2]
- id: surround_dtses_matrix
label: DTS ES Matrix
kind: action
params: []
decimal: [163]
hex: [0xA3]
- id: surround_direct
label: Direct
kind: action
params: []
decimal: [164]
hex: [0xA4]
- id: surround_neo6_music
label: DTS Neo6 Music
kind: action
params: []
decimal: [167]
hex: [0xA7]
- id: surround_dolby_ex
label: Dolby EX
kind: action
params: []
decimal: [168]
hex: [0xA8]
- id: surround_stereo_96
label: Stereo 96
kind: action
params: []
decimal: [169]
hex: [0xA9]
- id: late_night_on
label: Late Night On (DYN)
kind: action
params: []
decimal: [37]
hex: [0x25]
- id: late_night_off
label: Late Night Off (DYN)
kind: action
params: []
decimal: [38]
hex: [0x26]
- id: late_night_toggle
label: Late Night Toggle (DYN)
kind: action
params: []
decimal: [12]
hex: [0x0C]
- id: cinema_eq_toggle
label: Cinema EQ Toggle
kind: action
params: []
decimal: [99]
hex: [0x63]
- id: thx_toggle
label: THX Toggle
kind: action
params: []
decimal: [27]
hex: [0x1B]
# Tone and Speaker Trim
- id: bass_plus
label: Bass Plus
kind: action
params: []
decimal: [68]
hex: [0x44]
- id: bass_minus
label: Bass Minus
kind: action
params: []
decimal: [69]
hex: [0x45]
- id: treble_plus
label: Treble Plus
kind: action
params: []
decimal: [70]
hex: [0x46]
- id: treble_minus
label: Treble Minus
kind: action
params: []
decimal: [71]
hex: [0x47]
- id: subwoofer_plus
label: Subwoofer Plus
kind: action
params: []
decimal: [97]
hex: [0x61]
- id: subwoofer_minus
label: Subwoofer Minus
kind: action
params: []
decimal: [98]
hex: [0x62]
- id: surround_trim_plus
label: Surround Trim Plus
kind: action
params: []
decimal: [131]
hex: [0x83]
- id: surround_trim_minus
label: Surround Trim Minus
kind: action
params: []
decimal: [132]
hex: [0x84]
- id: center_plus
label: Center Trim Plus
kind: action
params: []
decimal: [129]
hex: [0x81]
- id: center_minus
label: Center Trim Minus
kind: action
params: []
decimal: [130]
hex: [0x82]
- id: preset_1
label: Preset 1
kind: action
params: []
decimal: [124]
hex: [0x7C]
- id: preset_2
label: Preset 2
kind: action
params: []
decimal: [125]
hex: [0x7D]
- id: preset_3
label: Preset 3
kind: action
params: []
decimal: [126]
hex: [0x7E]
- id: preset_4
label: Preset 4
kind: action
params: []
decimal: [127]
hex: [0x7F]
- id: preset_5
label: Preset 5
kind: action
params: []
decimal: [128]
hex: [0x80]
- id: enhanced_bass_on
label: Enhanced Bass On
kind: action
params: []
decimal: [156]
hex: [0x9C]
- id: enhanced_bass_off
label: Enhanced Bass Off
kind: action
params: []
decimal: [157]
hex: [0x9D]
- id: enhanced_bass_toggle
label: Enhanced Bass Toggle
kind: action
params: []
decimal: [133]
hex: [0x85]
# Zone Control
- id: zone_off
label: Zone Off
kind: action
params: []
decimal: [4]
hex: [0x04]
- id: zone_on
label: Zone On
kind: action
params: []
decimal: [5]
hex: [0x05]
- id: zone_toggle
label: Zone On/Off Toggle
kind: action
params: []
decimal: [134]
hex: [0x86]
- id: zone_volume_plus
label: Zone Volume Plus
kind: action
params: []
decimal: [139]
hex: [0x8B]
- id: zone_volume_minus
label: Zone Volume Minus
kind: action
params: []
decimal: [140]
hex: [0x8C]
- id: zone_mute_on
label: Zone Mute On
kind: action
params: []
decimal: [158]
hex: [0x9E]
- id: zone_mute_off
label: Zone Mute Off
kind: action
params: []
decimal: [159]
hex: [0x9F]
- id: zone_mute_toggle
label: Zone Mute Toggle
kind: action
params: []
decimal: [165]
hex: [0xA5]
- id: zone_source_minus
label: Zone Source Minus
kind: action
params: []
decimal: [135]
hex: [0x87]
- id: zone_source_plus
label: Zone Source Plus
kind: action
params: []
decimal: [141]
hex: [0x8D]
- id: zone_source_video_1
label: Zone Source Video 1
kind: action
params: []
decimal: [74]
hex: [0x4A]
- id: zone_source_video_2
label: Zone Source Video 2
kind: action
params: []
decimal: [75]
hex: [0x4B]
- id: zone_source_video_3
label: Zone Source Video 3
kind: action
params: []
decimal: [76]
hex: [0x4C]
- id: zone_source_video_4
label: Zone Source Video 4
kind: action
params: []
decimal: [77]
hex: [0x4D]
- id: zone_source_video_5
label: Zone Source Video 5
kind: action
params: []
decimal: [78]
hex: [0x4E]
- id: zone_source_video_6
label: Zone Source Video 6
kind: action
params: []
decimal: [79]
hex: [0x4F]
- id: zone_source_audio_1
label: Zone Source Audio 1
kind: action
params: []
decimal: [80]
hex: [0x50]
- id: zone_source_audio_2
label: Zone Source Audio 2
kind: action
params: []
decimal: [81]
hex: [0x51]
- id: zone_source_audio_3
label: Zone Source Audio 3
kind: action
params: []
decimal: [82]
hex: [0x52]
- id: zone_source_audio_4
label: Zone Source Audio 4
kind: action
params: []
decimal: [83]
hex: [0x53]
- id: zone_source_analog_71
label: Zone Source Analog 7.1
kind: action
params: []
decimal: [84]
hex: [0x54]
- id: zone_source_analog_71_toggle
label: Zone Source Analog 7.1 Toggle
kind: action
params: []
decimal: [137]
hex: [0x89]
# Tape Record Control
- id: tape_sticky_toggle
label: Tape Monitor Sticky Toggle
kind: action
params: []
decimal: [26]
hex: [0x1A]
- id: tape_nonsticky_toggle
label: Tape Monitor Non-Sticky Toggle
kind: action
params: []
decimal: [31]
hex: [0x1F]
- id: tape_off
label: Tape Monitor Off
kind: action
params: []
decimal: [39]
hex: [0x27]
- id: tape_sticky_on
label: Tape Monitor Sticky On
kind: action
params: []
decimal: [40]
hex: [0x28]
- id: tape_nonsticky_on
label: Tape Monitor Non-Sticky On
kind: action
params: []
decimal: [41]
hex: [0x29]
# Setup Menu Control
- id: setup_menu_toggle
label: Setup Menu Toggle
kind: action
params: []
decimal: [103]
hex: [0x67]
- id: cursor_up
label: Cursor Up
kind: action
params: []
decimal: [104]
hex: [0x68]
- id: cursor_down
label: Cursor Down
kind: action
params: []
decimal: [105]
hex: [0x69]
- id: cursor_left
label: Cursor Left
kind: action
params: []
decimal: [106]
hex: [0x6A]
- id: cursor_right
label: Cursor Right
kind: action
params: []
decimal: [107]
hex: [0x6B]
- id: cursor_select
label: Select
kind: action
params: []
decimal: [108]
hex: [0x6C]
- id: cursor_exit
label: Exit Without Save (ESC)
kind: action
params: []
decimal: [109]
hex: [0x6D]
- id: cursor_step_down
label: Cursor Step Down
kind: action
params: []
decimal: [114]
hex: [0x72]
- id: test_noise
label: Test Noise (CAL)
kind: action
params: []
decimal: [23]
hex: [0x17]
# Other
- id: front_panel_lock_toggle
label: Lock/Unlock Front Panel Toggle
kind: action
params: []
decimal: [145]
hex: [0x91]
- id: show_status_onscreen
label: Show Status On Screen
kind: action
params: []
decimal: [122]
hex: [0x7A]
- id: ping
label: Ping and Hello Response
kind: action
params: []
decimal: [80]
hex: [0x50]
# Multi-byte Commands
- id: set_main_volume
label: Set Main Volume
kind: action
params:
- name: level
type: integer
min: 10
max: 106
description: "10 = -90dB, 81 = -19dB, 100 = 0dB"
decimal: [180]
hex: [0xB4]
multi_byte: true
byte_2_decimal: "10-106"
- id: set_zone_volume
label: Set Zone Volume
kind: action
params:
- name: level
type: integer
min: 10
max: 100
description: "10 = -90dB, 81 = -19dB, 100 = 0dB"
decimal: [182]
hex: [0xB6]
multi_byte: true
byte_2_decimal: "10-100"
- id: set_plii_params
label: Set PLII Parameters
kind: action
params:
- name: panorama
type: integer
values: [0, 1]
description: "0 = Off, 1 = On"
- name: center_width
type: integer
min: 0
max: 7
description: "0 = Narrow, 7 = Wide"
- name: dimension
type: integer
min: 0
max: 6
description: "0 = Front biased, 6 = Max surround"
decimal: [184]
hex: [0xB8]
multi_byte: true
- id: set_neo6_params
label: Set Neo6 Parameters
kind: action
params:
- name: center_image
type: integer
min: 0
max: 5
description: "0 = Narrow, 5 = Wide"
decimal: [185]
hex: [0xB9]
multi_byte: true
- id: show_zone_status
label: Show Zone Status
kind: action
params: []
decimal: [166]
hex: [0xA6]
# Full Status Query (no preamble needed)
- id: request_full_status
label: Request Full Status Report
kind: query
params: []
decimal: [227]
hex: [0xE3]
note: "Do NOT send RS Enable preamble before this command"
Feedbacks
feedbacks:
- id: main_volume
label: Main Volume
type: integer
decimal_code: 225
hex_code: 0xE1
range: "10-106"
mapping: "10 = -90dB, 81 = -19dB, 100 = 0dB"
- id: mute_status
label: Mute Status
type: enum
decimal_code: 226
hex_code: 0xE2
values:
0: unmuted
1: muted
- id: current_source
label: Current Source
type: enum
decimal_code: 227
hex_code: 0xE3
values:
1: Video 1
2: Video 2
3: Video 3
4: Video 4
5: Video 5
6: Video 6
7: Audio 1
8: Audio 2
9: Audio 3
10: Audio 4
64: 7.1 Input
- id: power_status
label: Power Status
type: enum
decimal_code: 229
hex_code: 0xE5
values:
0: standby
1: on
- id: zone_source
label: Zone Source
type: enum
decimal_code: 230
hex_code: 0xE6
values:
1: Video 1
2: Video 2
3: Video 3
4: Video 4
5: Video 5
6: Video 6
- id: zone_volume
label: Zone Volume
type: integer
decimal_code: 232
hex_code: 0xE8
range: "10-100"
mapping: "10 = -90dB, 81 = -19dB, 100 = 0dB"
- id: zone_mute_status
label: Zone Mute Status
type: enum
decimal_code: 233
hex_code: 0xE9
values:
0: unmuted
1: muted
- id: dimmer_status
label: Dimmer Status
type: enum
decimal_code: 234
hex_code: 0xEA
values:
0: bright
1: dimmed
- id: surround_mode
label: Surround Mode
type: enum
decimal_code: 236
hex_code: 0xEC
values:
0: Direct
1: Dolby Pro Logic
2: Natural
3: Club
4: Concert
6: Party
7: Mono downmix
9: Surround 6.1
12: Stereo downmix
13: Pro Logic II Movie
14: Pro Logic II Music
15: Dolby Digital EX
16: Neo:6 Cinema
17: Matrix / Neo:6
20: Neo:6 Music
21: Stereo 96
23: Pro Logic IIx Music
24: Pro Logic IIx Movie
- id: audio_type
label: Current Audio Type
type: enum
decimal_code: 237
hex_code: 0xED
values:
2: Digital PCM
3: Dolby Digital
4: DTS
6: Noise
7: Analog
8: Digital Error
9: DTS-ES Matrix
10: DTS-ES Discrete
11: DTS 96/24
12: DTS 96 Matrix
13: DTS 96 Discrete
- id: input_type
label: Input Type
type: bitmask
decimal_code: 215
hex_code: 0xD7
description: "8-bit value encoding audio channel configuration and flags"
- id: input_method
label: Current Input Method
type: enum
decimal_code: 238
hex_code: 0xEE
values:
0: Non-balanced Analog
1: Coaxial
2: Optical
- id: late_night_status
label: Late Night (DYN)
type: enum
decimal_code: 239
hex_code: 0xEF
values:
0: compression off
1: compression on
- id: cinema_eq_status
label: Cinema EQ
type: enum
decimal_code: 240
hex_code: 0xF0
values:
0: off
1: on
- id: treble_trim
label: Treble Trim
type: integer
decimal_code: 242
hex_code: 0xF2
range: "0-24"
mapping: "0 = -12dB, 12 = 0dB, 24 = +12dB"
- id: bass_trim
label: Bass Trim
type: integer
decimal_code: 243
hex_code: 0xF3
range: "0-24"
mapping: "0 = -12dB, 12 = 0dB, 24 = +12dB"
- id: center_trim
label: Center Trim
type: integer
decimal_code: 244
hex_code: 0xF4
range: "0-24"
mapping: "0 = -12dB, 12 = 0dB, 24 = +12dB"
- id: surround_trim
label: Surround Trim
type: integer
decimal_code: 245
hex_code: 0xF5
range: "0-24"
mapping: "0 = -12dB, 12 = 0dB, 24 = +12dB"
- id: subwoofer_trim
label: Subwoofer Trim
type: integer
decimal_code: 246
hex_code: 0xF6
range: "0-24"
mapping: "0 = -12dB, 12 = 0dB, 24 = +12dB"
- id: trigger_1_status
label: Trigger 1 Status
type: enum
decimal_code: 247
hex_code: 0xF7
values:
0: inactive
1: active
- id: trigger_2_status
label: Trigger 2 Status
type: enum
decimal_code: 248
hex_code: 0xF8
values:
0: inactive
1: active
- id: video_format
label: Video Format
type: enum
decimal_code: 249
hex_code: 0xF9
values:
0: unknown
1: PAL
2: NTSC
- id: thx_status
label: THX Status
type: enum
decimal_code: 250
hex_code: 0xFA
values:
0: THX off
1: THX Cinema
2: THX Surround EX
3: THX Ultra2
4: THX Music
5: THX Games
- id: headphone_status
label: Headphone Status
type: enum
decimal_code: 224
hex_code: 0xE0
values:
0: not connected
1: connected
- id: plii_params
label: PLII Parameters
type: compound
decimal_code: 216
hex_code: 0xD8
fields:
panorama: { type: enum, values: { 0: Off, 1: On } }
center_width: { type: integer, range: "0-7", description: "0 = Narrow, 7 = Wide" }
dimension: { type: integer, range: "0-6", description: "0 = 3, 6 = -3" }
Events
events:
description: "Unsolicited feedback sent out the RS-232 port whenever a parameter or function status changes. Format: <command_code> <data> <255> where 255 indicates end of transmission block."
note: "All feedback entries in the Feedbacks section above are also sent as unsolicited events on state change."
Macros
macros:
- id: universal_stereo
label: Universal Stereo
description: "Ensures surround mode goes to stereo regardless of input type"
steps:
- action: surround_direct
decimal: [224, 82, 83, 33, 164]
- action: surround_stereo
decimal: [224, 82, 83, 33, 43]
crestron_hex: "\\xE0\\x52\\x53\\x21\\xA4\\xE0\\x52\\x53\\x21\\x2B"
Safety
confirmation_required_for: []
interlocks: []
# UNRESOLVED: no safety warnings or interlock procedures found in source
Notes
- Binary protocol — all commands are raw byte values, not ASCII strings.
- RS Enable preamble (decimal
224 82 83 33/ hexE0 52 53 21) must precede every command except the full status query. - No carriage returns or line feeds between bytes.
- Feedback format:
<parameter_code> <data> <255>where 255 marks end of block. - Full status query (decimal 227) does NOT require RS Enable preamble. Response starts with byte 223 (start marker) followed by 255-separated data blocks.
- Source also covers the Halo C 1 — identical command set.
- Volume byte mapping: value 10 = -90dB through value 100 = 0dB (linear in the byte but non-linear in dB; value 81 = -19dB).
- Surround mode feedback value space has gaps (e.g. 5, 8, 10, 11, 18, 19, 22 are undefined).
Provenance
source_domains:
- cdn.shopify.com
source_urls:
- "https://cdn.shopify.com/s/files/1/0763/0864/4159/files/C1_C2_RS232Codes.pdf?v=1719694110"
retrieved_at: 2026-05-21T16:56:39.590Z
last_checked_at: 2026-05-31T07:00:29.370Z
Verification Summary
verdict: verified
checked_at: 2026-05-31T07:00:29.370Z
matched_actions: 108
action_count: 108
confidence: medium
summary: "All 108 spec actions matched literal command codes from source; transport parameters verified; source command set fully represented. (5 unresolved item(s) noted in Known Gaps.)"
Known Gaps
- "no safety warnings or interlock procedures found in source"
- "firmware version compatibility not stated in source"
- "maximum command rate / minimum inter-command delay not stated"
- "error recovery or timeout behavior not documented"
- "no TCP/IP control documented — serial only"
From the AI4AV catalog (https://ai4av.net) · ODbL-1.0