BenQ MS531 RS-232 / IP control commands

Summary

BenQ projector RS-232 command control via serial (D-Sub 9) or LAN (TCP port 8000). Supports power, source selection, audio, picture settings, lamp control, 3D sync, and operation settings. Command format: <CR>*<command>=<value>#<CR>. Available functions vary by model; this spec covers commands marked supported for these models.

Transport

protocols:
  - serial
  - tcp
serial:
  baud_rate: 9600  # configurable: 2400/4800/9600/14400/19200/38400/57600/115200
  data_bits: 8
  parity: none
  stop_bits: 1
  flow_control: none
addressing:
  port: 8000
auth:
  type: none  # inferred: no auth procedure in source

Traits

- powerable  # power on/off commands present
- routable  # source selection commands present
- queryable  # query commands returning state present
- levelable  # volume, contrast, brightness, color, sharpness +/- commands present

Actions

- id: power_on
  label: Power On
  kind: action
  command: "<CR>*pow=on#<CR>"
  params: []

- id: power_off
  label: Power Off
  kind: action
  command: "<CR>*pow=off#<CR>"
  params: []

- id: select_source_rgb
  label: Select Source COMPUTER/YPbPr
  kind: action
  command: "<CR>*sour=RGB#<CR>"
  params: []

- id: select_source_rgb2
  label: Select Source COMPUTER 2/YPbPr2
  kind: action
  command: "<CR>*sour=RGB2#<CR>"
  params: []

- id: select_source_hdmi
  label: Select Source HDMI/MHL
  kind: action
  command: "<CR>*sour=hdmi#<CR>"
  params: []

- id: select_source_hdmi2
  label: Select Source HDMI 2/MHL2
  kind: action
  command: "<CR>*sour=hdmi2#<CR>"
  params: []

- id: select_source_composite
  label: Select Source Composite
  kind: action
  command: "<CR>*sour=vid#<CR>"
  params: []

- id: select_source_svideo
  label: Select Source S-Video
  kind: action
  command: "<CR>*sour=svid#<CR>"
  params: []

- id: mute_on
  label: Mute On
  kind: action
  command: "<CR>*mute=on#<CR>"
  params: []

- id: mute_off
  label: Mute Off
  kind: action
  command: "<CR>*mute=off#<CR>"
  params: []

- id: volume_up
  label: Volume Up
  kind: action
  command: "<CR>*vol=+#<CR>"
  params: []

- id: volume_down
  label: Volume Down
  kind: action
  command: "<CR>*vol=-#<CR>"
  params: []

- id: audio_source_off
  label: Audio Pass Through Off
  kind: action
  command: "<CR>*audiosour=off#<CR>"
  params: []

- id: audio_source_rgb
  label: Audio Source Computer1
  kind: action
  command: "<CR>*audiosour=RGB#<CR>"
  params: []

- id: audio_source_rgb2
  label: Audio Source Computer2
  kind: action
  command: "<CR>*audiosour=RGB2#<CR>"
  params: []

- id: audio_source_vid
  label: Audio Source Video/S-Video
  kind: action
  command: "<CR>*audiosour=vid#<CR>"
  params: []

- id: audio_source_hdmi
  label: Audio Source HDMI
  kind: action
  command: "<CR>*audiosour=hdmi#<CR>"
  params: []

- id: audio_source_hdmi2
  label: Audio Source HDMI2
  kind: action
  command: "<CR>*audiosour=hdmi2#<CR>"
  params: []

- id: picture_mode_presentation
  label: Picture Mode Presentation
  kind: action
  command: "<CR>*appmod=preset#<CR>"
  params: []

- id: picture_mode_srgb
  label: Picture Mode sRGB
  kind: action
  command: "<CR>*appmod=srgb#<CR>"
  params: []

- id: picture_mode_bright
  label: Picture Mode Bright
  kind: action
  command: "<CR>*appmod=bright#<CR>"
  params: []

- id: picture_mode_cinema
  label: Picture Mode Cinema
  kind: action
  command: "<CR>*appmod=cine#<CR>"
  params: []

- id: picture_mode_user1
  label: Picture Mode User1
  kind: action
  command: "<CR>*appmod=user1#<CR>"
  params: []

- id: picture_mode_user2
  label: Picture Mode User2
  kind: action
  command: "<CR>*appmod=user2#<CR>"
  params: []

- id: picture_mode_3d
  label: Picture Mode 3D
  kind: action
  command: "<CR>*appmod=threed#<CR>"
  params: []

- id: contrast_up
  label: Contrast Up
  kind: action
  command: "<CR>*con=+#<CR>"
  params: []

- id: contrast_down
  label: Contrast Down
  kind: action
  command: "<CR>*con=-#<CR>"
  params: []

- id: brightness_up
  label: Brightness Up
  kind: action
  command: "<CR>*bri=+#<CR>"
  params: []

- id: brightness_down
  label: Brightness Down
  kind: action
  command: "<CR>*bri=-#<CR>"
  params: []

- id: color_up
  label: Color Up
  kind: action
  command: "<CR>*color=+#<CR>"
  params: []

- id: color_down
  label: Color Down
  kind: action
  command: "<CR>*color=-#<CR>"
  params: []

- id: sharpness_up
  label: Sharpness Up
  kind: action
  command: "<CR>*sharp=+#<CR>"
  params: []

- id: sharpness_down
  label: Sharpness Down
  kind: action
  command: "<CR>*sharp=-#<CR>"
  params: []

- id: color_temp_warm
  label: Color Temperature Warm
  kind: action
  command: "<CR>*ct=warm#<CR>"
  params: []

- id: color_temp_normal
  label: Color Temperature Normal
  kind: action
  command: "<CR>*ct=normal#<CR>"
  params: []

- id: color_temp_cool
  label: Color Temperature Cool
  kind: action
  command: "<CR>*ct=cool#<CR>"
  params: []

- id: color_temp_native
  label: Color Temperature Lamp Native
  kind: action
  command: "<CR>*ct=native#<CR>"
  params: []

- id: aspect_4_3
  label: Aspect Ratio 4:3
  kind: action
  command: "<CR>*asp=4:3#<CR>"
  params: []

- id: aspect_16_9
  label: Aspect Ratio 16:9
  kind: action
  command: "<CR>*asp=16:9#<CR>"
  params: []

- id: aspect_16_10
  label: Aspect Ratio 16:10
  kind: action
  command: "<CR>*asp=16:10#<CR>"
  params: []

- id: aspect_auto
  label: Aspect Ratio Auto
  kind: action
  command: "<CR>*asp=AUTO#<CR>"
  params: []

- id: aspect_real
  label: Aspect Ratio Real
  kind: action
  command: "<CR>*asp=REAL#<CR>"
  params: []

- id: digital_zoom_in
  label: Digital Zoom In
  kind: action
  command: "<CR>*zoomI#<CR>"
  params: []

- id: digital_zoom_out
  label: Digital Zoom Out
  kind: action
  command: "<CR>*zoomO#<CR>"
  params: []

- id: auto
  label: Auto
  kind: action
  command: "<CR>*auto#<CR>"
  params: []

- id: brilliant_color_on
  label: Brilliant Color On
  kind: action
  command: "<CR>*BC=on#<CR>"
  params: []

- id: brilliant_color_off
  label: Brilliant Color Off
  kind: action
  command: "<CR>*BC=off#<CR>"
  params: []

- id: position_front_table
  label: Projector Position Front Table
  kind: action
  command: "<CR>*pp=FT#<CR>"
  params: []

- id: position_rear_table
  label: Projector Position Rear Table
  kind: action
  command: "<CR>*pp=RE#<CR>"
  params: []

- id: position_rear_ceiling
  label: Projector Position Rear Ceiling
  kind: action
  command: "<CR>*pp=RC#<CR>"
  params: []

- id: position_front_ceiling
  label: Projector Position Front Ceiling
  kind: action
  command: "<CR>*pp=FC#<CR>"
  params: []

- id: quick_auto_search_on
  label: Quick Auto Search On
  kind: action
  command: "<CR>*QAS=on#<CR>"
  params: []

- id: quick_auto_search_off
  label: Quick Auto Search Off
  kind: action
  command: "<CR>*QAS=off#<CR>"
  params: []

- id: direct_power_on_on
  label: Direct Power On Enable
  kind: action
  command: "<CR>*directpower=on#<CR>"
  params: []

- id: direct_power_on_off
  label: Direct Power On Disable
  kind: action
  command: "<CR>*directpower=off#<CR>"
  params: []

- id: signal_power_on_on
  label: Signal Power On Enable
  kind: action
  command: "<CR>*autopower=on#<CR>"
  params: []

- id: signal_power_on_off
  label: Signal Power On Disable
  kind: action
  command: "<CR>*autopower=off#<CR>"
  params: []

- id: standby_monitor_out_on
  label: Standby Monitor Out On
  kind: action
  command: "<CR>*standbymnt=on#<CR>"
  params: []

- id: standby_monitor_out_off
  label: Standby Monitor Out Off
  kind: action
  command: "<CR>*standbymnt=off#<CR>"
  params: []

- id: set_baud_2400
  label: Set Baud Rate 2400
  kind: action
  command: "<CR>*baud=2400#<CR>"
  params: []

- id: set_baud_4800
  label: Set Baud Rate 4800
  kind: action
  command: "<CR>*baud=4800#<CR>"
  params: []

- id: set_baud_9600
  label: Set Baud Rate 9600
  kind: action
  command: "<CR>*baud=9600#<CR>"
  params: []

- id: set_baud_14400
  label: Set Baud Rate 14400
  kind: action
  command: "<CR>*baud=14400#<CR>"
  params: []

- id: set_baud_19200
  label: Set Baud Rate 19200
  kind: action
  command: "<CR>*baud=19200#<CR>"
  params: []

- id: set_baud_38400
  label: Set Baud Rate 38400
  kind: action
  command: "<CR>*baud=38400#<CR>"
  params: []

- id: set_baud_57600
  label: Set Baud Rate 57600
  kind: action
  command: "<CR>*baud=57600#<CR>"
  params: []

- id: set_baud_115200
  label: Set Baud Rate 115200
  kind: action
  command: "<CR>*baud=115200#<CR>"
  params: []

- id: lamp_mode_normal
  label: Lamp Mode Normal
  kind: action
  command: "<CR>*lampm=lnor#<CR>"
  params: []

- id: lamp_mode_eco
  label: Lamp Mode Eco
  kind: action
  command: "<CR>*lampm=eco#<CR>"
  params: []

- id: lamp_mode_smart_eco
  label: Lamp Mode Smart Eco (ImageCare)
  kind: action
  command: "<CR>*lampm=seco#<CR>"
  params: []

- id: blank_on
  label: Blank On
  kind: action
  command: "<CR>*blank=on#<CR>"
  params: []

- id: blank_off
  label: Blank Off
  kind: action
  command: "<CR>*blank=off#<CR>"
  params: []

- id: freeze_on
  label: Freeze On
  kind: action
  command: "<CR>*freeze=on#<CR>"
  params: []

- id: freeze_off
  label: Freeze Off
  kind: action
  command: "<CR>*freeze=off#<CR>"
  params: []

- id: menu_on
  label: Menu On
  kind: action
  command: "<CR>*menu=on#<CR>"
  params: []

- id: menu_off
  label: Menu Off
  kind: action
  command: "<CR>*menu=off#<CR>"
  params: []

- id: nav_up
  label: Navigate Up
  kind: action
  command: "<CR>*up#<CR>"
  params: []

- id: nav_down
  label: Navigate Down
  kind: action
  command: "<CR>*down#<CR>"
  params: []

- id: nav_right
  label: Navigate Right
  kind: action
  command: "<CR>*right#<CR>"
  params: []

- id: nav_left
  label: Navigate Left
  kind: action
  command: "<CR>*left#<CR>"
  params: []

- id: nav_enter
  label: Navigate Enter
  kind: action
  command: "<CR>*enter#<CR>"
  params: []

- id: 3d_sync_off
  label: 3D Sync Off
  kind: action
  command: "<CR>*3d=off#<CR>"
  params: []

- id: 3d_auto
  label: 3D Auto
  kind: action
  command: "<CR>*3d=auto#<CR>"
  params: []

- id: 3d_top_bottom
  label: 3D Sync TopBottom
  kind: action
  command: "<CR>*3d=tb#<CR>"
  params: []

- id: 3d_frame_sequential
  label: 3D Sync Frame Sequential
  kind: action
  command: "<CR>*3d=fs#<CR>"
  params: []

- id: 3d_frame_packing
  label: 3D Framepacking
  kind: action
  command: "<CR>*3d=fp#<CR>"
  params: []

- id: 3d_side_by_side
  label: 3D Side by Side
  kind: action
  command: "<CR>*3d=sbs#<CR>"
  params: []

- id: 3d_inverter_disable
  label: 3D Inverter Disable
  kind: action
  command: "<CR>*3d=da#<CR>"
  params: []

- id: 3d_inverter
  label: 3D Inverter
  kind: action
  command: "<CR>*3d=iv#<CR>"
  params: []

- id: instant_on_on
  label: Instant On Enable
  kind: action
  command: "<CR>*ins=on#<CR>"
  params: []

- id: instant_on_off
  label: Instant On Disable
  kind: action
  command: "<CR>*ins=off#<CR>"
  params: []

- id: high_altitude_on
  label: High Altitude Mode On
  kind: action
  command: "<CR>*Highaltitude=on#<CR>"
  params: []

- id: high_altitude_off
  label: High Altitude Mode Off
  kind: action
  command: "<CR>*Highaltitude=off#<CR>"
  params: []

Feedbacks

- id: power_state
  label: Power Status
  type: enum
  command: "<CR>*pow=?#<CR>"
  values: [on, off]

- id: current_source
  label: Current Source
  type: enum
  command: "<CR>*sour=?#<CR>"
  values: [RGB, RGB2, hdmi, hdmi2, vid, svid]

- id: mute_status
  label: Mute Status
  type: enum
  command: "<CR>*mute=?#<CR>"
  values: [on, off]

- id: volume_status
  label: Volume Status
  type: string
  command: "<CR>*vol=?#<CR>"

- id: audio_source_status
  label: Audio Source Status
  type: enum
  command: "<CR>*audiosour=?#<CR>"
  values: [off, RGB, RGB2, vid, hdmi, hdmi2]

- id: picture_mode
  label: Picture Mode
  type: enum
  command: "<CR>*appmod=?#<CR>"
  values: [preset, srgb, bright, cine, user1, user2, threed]

- id: contrast_value
  label: Contrast Value
  type: string
  command: "<CR>*con=?#<CR>"

- id: brightness_value
  label: Brightness Value
  type: string
  command: "<CR>*bri=?#<CR>"

- id: color_value
  label: Color Value
  type: string
  command: "<CR>*color=?#<CR>"

- id: sharpness_value
  label: Sharpness Value
  type: string
  command: "<CR>*sharp=?#<CR>"

- id: color_temperature
  label: Color Temperature Status
  type: enum
  command: "<CR>*ct=?#<CR>"
  values: [warm, normal, cool, native]

- id: aspect_status
  label: Aspect Ratio Status
  type: enum
  command: "<CR>*asp=?#<CR>"
  values: ["4:3", "16:9", "16:10", AUTO, REAL]

- id: brilliant_color_status
  label: Brilliant Color Status
  type: enum
  command: "<CR>*BC=?#<CR>"
  values: [on, off]

- id: projector_position
  label: Projector Position Status
  type: enum
  command: "<CR>*pp=?#<CR>"
  values: [FT, RE, RC, FC]

- id: quick_auto_search_status
  label: Quick Auto Search Status
  type: enum
  command: "<CR>*QAS=?#<CR>"
  values: [on, off]

- id: direct_power_on_status
  label: Direct Power On Status
  type: enum
  command: "<CR>*directpower=?#<CR>"
  values: [on, off]

- id: signal_power_on_status
  label: Signal Power On Status
  type: enum
  command: "<CR>*autopower=?#<CR>"
  values: [on, off]

- id: standby_monitor_out_status
  label: Standby Monitor Out Status
  type: enum
  command: "<CR>*standbymnt=?#<CR>"
  values: [on, off]

- id: current_baud_rate
  label: Current Baud Rate
  type: enum
  command: "<CR>*baud=?#<CR>"
  values: [2400, 4800, 9600, 14400, 19200, 38400, 57600, 115200]

- id: lamp_hours
  label: Lamp Hours
  type: integer
  command: "<CR>*ltim=?#<CR>"

- id: lamp_mode_status
  label: Lamp Mode Status
  type: enum
  command: "<CR>*lampm=?#<CR>"
  values: [lnor, eco, seco]

- id: model_name
  label: Model Name
  type: string
  command: "<CR>*modelname=?#<CR>"

- id: blank_status
  label: Blank Status
  type: enum
  command: "<CR>*blank=?#<CR>"
  values: [on, off]

- id: freeze_status
  label: Freeze Status
  type: enum
  command: "<CR>*freeze=?#<CR>"
  values: [on, off]

- id: 3d_status
  label: 3D Sync Status
  type: enum
  command: "<CR>*3d=?#<CR>"
  values: [off, auto, tb, fs, fp, sbs, da, iv]

- id: instant_on_status
  label: Instant On Status
  type: enum
  command: "<CR>*ins=?#<CR>"
  values: [on, off]

- id: high_altitude_status
  label: High Altitude Mode Status
  type: enum
  command: "<CR>*Highaltitude=?#<CR>"
  values: [on, off]

Variables

# UNRESOLVED: no discrete settable numeric parameters found - volume/contrast/brightness/color/sharpness use +/- relative commands only

Events

# UNRESOLVED: no unsolicited notification protocol documented in source

Macros

# UNRESOLVED: no multi-step sequences documented in source

Safety

confirmation_required_for: []
interlocks: []
# UNRESOLVED: source notes commands work if standby power is 0.5W or supported baud rate is set;
# no interlock or power-on sequencing requirements documented

Notes

Command format: <CR>*<command>=<value>#<CR>. Case-insensitive.
Error responses: Illegal format (bad syntax), Unsupported item (valid but not for this model), Block item (valid but cannot execute under current conditions).
Serial via LAN uses same command set over TCP port 8000.
HDBaseT passthrough uses same serial settings.
Source selection and features vary by projector model; only commands marked "Yes" in source are included.
Volume, contrast, brightness, color, sharpness use relative +/- commands — no absolute value set commands documented.

Provenance

source_domains:
  - esupportdownload.benq.com
  - manualslib.com
  - audiogeneral.com
source_urls:
  - "https://esupportdownload.benq.com/esupport/Projector/Control%20Protocols/BS5050/RS232%20Control%20Guide_0_Windows10_Windows7_Windows8.pdf"
  - https://www.manualslib.com/manual/1752140/Benq-St430k-Series.html
  - https://www.audiogeneral.com/BenQ/rs232_commands_generic_082613.pdf
retrieved_at: 2026-05-14T20:25:55.045Z
last_checked_at: 2026-06-02T21:51:22.233Z

Verification Summary

verdict: verified
checked_at: 2026-06-02T21:51:22.233Z
matched_actions: 93
action_count: 93
confidence: medium
summary: "All 93 spec actions from command table for MS531/BS5050/ES6540 series. (10 unresolved item(s) noted in Known Gaps.)"

Known Gaps

- "exact model mapping for \"ST 550 650 430 K\" not found in source — source lists MS531/BS5050/ES6540/MS521H/MX532/MW533/TW533/MH534/TH534"
- "firmware version compatibility not stated"
- "response format beyond error strings not documented"
- "no discrete settable numeric parameters found - volume/contrast/brightness/color/sharpness use +/- relative commands only"
- "no unsolicited notification protocol documented in source"
- "no multi-step sequences documented in source"
- "source notes commands work if standby power is 0.5W or supported baud rate is set;"
- "exact response format for query commands beyond error strings"
- "model name \"ST 550 650 430 K\" not found in source document"
- "lamp mode response value mapping (lnor/eco/seco) unconfirmed"

From the AI4AV catalog (https://ai4av.net) · ODbL-1.0

BenQ ST 550 650 430 K Control Spec

Compatible models