Summary

The LG 50QNED74BAA Series is a commercial flat-panel display controllable over an RS-232 (UART) serial interface at 9600 baud, 8N1, ASCII. This spec enumerates the 26 ASCII command mnemonics the source documents for power, input selection, picture/sound/tile configuration, and device-state queries.

Transport

protocols:
  - serial
serial:
  baud_rate: 9600
  data_bits: 8
  parity: none
  stop_bits: 1
  flow_control: none
  communication_code: ASCII
auth:
  type: none  # inferred: no auth procedure in source

Traits

- powerable   # inferred from k a (power) command examples
- routable    # inferred from k b (input select) command examples
- queryable   # inferred from FF-read status queries (k a, k z, d l, d n, d p)
- levelable   # inferred from k f/k g/k h/k i/k j/k k/k t (volume, contrast, brightness, color, tint, sharpness, balance) command examples

Actions

- id: power_set
  label: Power Set
  kind: action
  command: "ka {id} {data}\r"
  params:
    - name: id
      type: integer
      description: Set ID (0 = broadcast to all products, 1-99 = specific product)
    - name: data
      type: integer
      enum: [0, 1]
      description: Power state (0 = Power Off, 1 = Power On)

- id: power_query
  label: Power Status Query
  kind: query
  command: "ka {id} FF\r"
  params:
    - name: id
      type: integer
      description: Set ID (0-99)

- id: input_select
  label: Input Select (Main Picture)
  kind: action
  command: "kb {id} {data}\r"
  params:
    - name: id
      type: integer
      description: Set ID (0-99)
    - name: data
      type: integer
      enum: [2, 4, 5, 6, 7, 8, 9]
      description: Input source (2=AV, 4=Component 1, 5=Component 2, 6=RGB DTV, 7=RGB PC, 8=HDMI DTV, 9=HDMI PC)

- id: aspect_ratio
  label: Aspect Ratio (Main Picture Format)
  kind: action
  command: "kc {id} {data}\r"
  params:
    - name: id
      type: integer
      description: Set ID (0-99)
    - name: data
      type: integer
      enum: [1, 2, 3, 4, 5, 6, 7, 8, 9]
      description: Aspect ratio (1=Normal 4:3, 2=Wide 16:9, 3=Horizon/Spectacle, 4=Zoom1, 5=Zoom2, 6=Original, 7=14:9, 8=Full/Europe, 9=1:1 PC)

- id: screen_mute
  label: Screen Mute
  kind: action
  command: "kd {id} {data}\r"
  params:
    - name: id
      type: integer
      description: Set ID (0-99)
    - name: data
      type: integer
      enum: [0, 1]
      description: Screen mute (0 = picture on, 1 = picture off)

- id: volume_mute
  label: Volume Mute
  kind: action
  command: "ke {id} {data}\r"
  params:
    - name: id
      type: integer
      description: Set ID (0-99)
    - name: data
      type: integer
      enum: [0, 1]
      description: Volume mute (0 = mute on / volume off, 1 = mute off / volume on)

- id: volume_control
  label: Volume Control
  kind: action
  command: "kf {id} {data}\r"
  params:
    - name: id
      type: integer
      description: Set ID (0-99)
    - name: data
      type: integer
      min: 0
      max: 100
      description: Volume step 0-100; transmitted as 2-char hex byte 00H-64H. Real-data mapping: 0x00=Step 0, 0x0A=Step 10, 0x0F=Step 15, 0x10=Step 16, 0x64=Step 100.

- id: contrast
  label: Contrast
  kind: action
  command: "kg {id} {data}\r"
  params:
    - name: id
      type: integer
      description: Set ID (0-99)
    - name: data
      type: integer
      min: 0
      max: 100
      description: Contrast step 0-100; transmitted as 2-char hex byte 00H-64H (mapping 0/0x0A/0x0F/0x10/0x64 = Step 0/10/15/16/100)

- id: brightness
  label: Brightness
  kind: action
  command: "kh {id} {data}\r"
  params:
    - name: id
      type: integer
      description: Set ID (0-99)
    - name: data
      type: integer
      min: 0
      max: 100
      description: Brightness step 0-100; transmitted as 2-char hex byte 00H-64H (mapping 0/0x0A/0x0F/0x10/0x64 = Step 0/10/15/16/100)

- id: color
  label: Color (Video only)
  kind: action
  command: "ki {id} {data}\r"
  params:
    - name: id
      type: integer
      description: Set ID (0-99)
    - name: data
      type: integer
      min: 0
      max: 100
      description: Color step 0-100; transmitted as 2-char hex byte 00H-64H (mapping 0/0x0A/0x0F/0x10/0x64 = Step 0/10/15/16/100; video input only)

- id: tint
  label: Tint (Video only)
  kind: action
  command: "kj {id} {data}\r"
  params:
    - name: id
      type: integer
      description: Set ID (0-99)
    - name: data
      type: integer
      min: 0
      max: 100
      description: Tint 0-100; transmitted as 2-char hex byte 00H-64H (0x00=Red -50, 0x64=Green +50; video input only)

- id: sharpness
  label: Sharpness (Video only)
  kind: action
  command: "kk {id} {data}\r"
  params:
    - name: id
      type: integer
      description: Set ID (0-99)
    - name: data
      type: integer
      min: 0
      max: 100
      description: Sharpness step 0-100; transmitted as 2-char hex byte 00H-64H (mapping 0/0x0A/0x0F/0x10/0x64 = Step 0/10/15/16/100; video input only)

- id: osd_select
  label: OSD Select
  kind: action
  command: "kl {id} {data}\r"
  params:
    - name: id
      type: integer
      description: Set ID (0-99)
    - name: data
      type: integer
      enum: [0, 1]
      description: OSD (0 = OSD Off, 1 = OSD On)

- id: remote_lock
  label: Remote Lock / Key Lock
  kind: action
  command: "km {id} {data}\r"
  params:
    - name: id
      type: integer
      description: Set ID (0-99)
    - name: data
      type: integer
      enum: [0, 1]
      description: Lock state (0 = Off, 1 = On; when controlling via RS-232C, also locks the remote control and the local keys)

- id: balance
  label: Balance
  kind: action
  command: "kt {id} {data}\r"
  params:
    - name: id
      type: integer
      description: Set ID (0-99)
    - name: data
      type: integer
      min: 0
      max: 100
      description: Balance 0-100; transmitted as 2-char hex byte 00H-64H (0x00=L50, 0x64=R50)

- id: color_temperature
  label: Color Temperature
  kind: action
  command: "ku {id} {data}\r"
  params:
    - name: id
      type: integer
      description: Set ID (0-99)
    - name: data
      type: integer
      enum: [0, 1, 2, 3]
      description: Color temperature preset (0 = Normal, 1 = Cool, 2 = Warm, 3 = User)

- id: abnormal_state
  label: Abnormal State Query
  kind: query
  command: "kz {id} FF\r"
  params:
    - name: id
      type: integer
      description: Set ID (0-99)

- id: ism_mode
  label: ISM Mode (Afterimage Prevention)
  kind: action
  command: "jp {id} {data}\r"
  params:
    - name: id
      type: integer
      description: Set ID (0-99)
    - name: data
      type: integer
      enum: [0, 1, 2, 4, 8]
      description: ISM mode (1=Inversion, 2=Orbiter, 4=White Wash, 8=Normal; command reference table lists data range 00H-08H)

- id: auto_config
  label: Auto Configuration
  kind: action
  command: "ju {id} {data}\r"
  params:
    - name: id
      type: integer
      description: Set ID (0-99)
    - name: data
      type: integer
      enum: [1]
      description: Trigger (1 = to set; auto-adjusts picture position and minimizes image shaking; works only in RGB(PC) mode)

- id: send_ir_key
  label: Send IR Remote Key Code
  kind: action
  command: "mc {id} {data}\r"
  params:
    - name: id
      type: integer
      description: Set ID (0-99)
    - name: data
      type: string
      description: IR key code as 2-character uppercase hex string (see IR Codes table in Notes)

- id: tile_mode
  label: Tile Mode
  kind: action
  command: "dd {id} {data}\r"
  params:
    - name: id
      type: integer
      description: Set ID (0-99)
    - name: data
      type: string
      enum: ["00", "12", "13", "14", "21", "22", "23", "24", "31", "32", "33", "34", "41", "42", "43", "44"]
      description: Tile mode (00=Tile mode off; otherwise column-row, e.g. 12=1col×2row, 13=1×3, 14=1×4, 21=2×1, 22=2×2, 23=2×3, 24=2×4, 31=3×1, 32=3×2, 33=3×3, 34=3×4, 41=4×1, 42=4×2, 43=4×3, 44=4×4; data of the form 0X or X0 is rejected except 00)

- id: tile_h_size
  label: Tile Horizontal Size
  kind: action
  command: "dg {id} {data}\r"
  params:
    - name: id
      type: integer
      description: Set ID (0-99)
    - name: data
      type: integer
      min: 0
      max: 100
      description: Tile H size 0-100; transmitted as 2-char hex byte 00H-64H

- id: tile_v_size
  label: Tile Vertical Size
  kind: action
  command: "dh {id} {data}\r"
  params:
    - name: id
      type: integer
      description: Set ID (0-99)
    - name: data
      type: integer
      min: 0
      max: 100
      description: Tile V size 0-100; transmitted as 2-char hex byte 00H-64H

- id: tile_id_set
  label: Tile ID Set
  kind: action
  command: "di {id} {data}\r"
  params:
    - name: id
      type: integer
      description: Set ID (0-99)
    - name: data
      type: integer
      min: 0
      max: 16
      description: Tile ID 0-16; transmitted as 2-char hex byte 00H-10H

- id: elapsed_time
  label: Elapsed Time Return
  kind: query
  command: "dl {id} FF\r"
  params:
    - name: id
      type: integer
      description: Set ID (0-99)

- id: temperature
  label: Temperature Value
  kind: query
  command: "dn {id} FF\r"
  params:
    - name: id
      type: integer
      description: Set ID (0-99)

- id: lamp_fault
  label: Lamp Fault Check
  kind: query
  command: "dp {id} FF\r"
  params:
    - name: id
      type: integer
      description: Set ID (0-99)

Feedbacks

- id: power_state
  type: enum
  values: [off, on]
  description: Returned by power_query (ka ... FF). Data 0 = Power Off, 1 = Power On.

- id: abnormal_state
  type: enum
  values: [normal, no_signal_power_on, off_by_remote, off_by_sleep_timer, off_by_rs232, ac_down, off_by_off_timer, off_by_auto_off]
  description: Returned by abnormal_state query (kz ... FF). Data 0=Normal (power on and signal exist), 1=No signal (power on), 2=Off by remote control, 3=Off by sleep time function, 4=Off by RS-232C function, 6=AC down, 8=Off by off time function, 9=Off by auto off function.

- id: elapsed_time_hours
  type: integer
  description: Returned by elapsed_time query (dl ... FF). Hex value; represents used hours.

- id: temperature_value
  type: integer
  description: Returned by temperature query (dn ... FF). 1-byte hex inside-temperature reading.

- id: lamp_fault_state
  type: enum
  values: [fault, ok]
  description: Returned by lamp_fault query (dp ... FF). Data 0 = Lamp Fault, 1 = Lamp OK.

Variables

# UNRESOLVED: no discrete settable parameters beyond the per-action data fields are documented in the source.

Events

# UNRESOLVED: no unsolicited notification mechanism is described in the source.

Macros

# UNRESOLVED: no multi-step sequences are described in the source.

Safety

confirmation_required_for: []
interlocks: []
# UNRESOLVED: no safety warnings, interlock procedures, or power-on sequencing requirements are documented in the source.

Notes

Command Format

All commands follow this ASCII frame:

[Command1][Command2][ ][Set ID][ ][Data][Cr]
  • Command1: first command character — one of j, k, m, d.
  • Command2: second command character (defines the operation).
  • Set ID: device address. Range 1–99; set 0 to broadcast to all products. When broadcasting to more than one device, do not check the ACK — every device replies and the messages collide.
  • Data: command data. Transmit FF to read current status of any command.
  • Cr: carriage return, ASCII 0x0D.
  • Inter-field space is ASCII 0x20.

OK Acknowledgement

[Command2][ ][Set ID][ ][OK][Data][x]

In read mode (Data = FF), Data carries the present status. In write mode, Data echoes the value sent by the controller.

Error Acknowledgement

[Command2][ ][Set ID][ ][NG][Data][x]

Returned when the command cannot be processed.

IR Codes (data values for send_ir_key)

Code (Hex) Function Note
00 L R/C Button
01 M R/C Button
02 VOL (−) R/C Button
03 VOL (+) R/C Button
08 POWER ON/OFF R/C Button (Power On/Off)
C4 POWER ON Discrete IR Code (only Power On)
C5 POWER OFF Discrete IR Code (only Power Off)
09 MUTE R/C Button
98 AV R/C Button
0B INPUT R/C Button
0E SLEEP R/C Button
43 MENU R/C Button
5B EXIT R/C Button
6E PSM R/C Button
44 SET R/C Button
10 Number Key 0 R/C Button
11 Number Key 1 R/C Button
12 Number Key 2 R/C Button
13 Number Key 3 R/C Button
14 Number Key 4 R/C Button
15 Number Key 5 R/C Button
16 Number Key 6 R/C Button
17 Number Key 7 R/C Button
18 Number Key 8 R/C Button
19 Number Key 9 R/C Button
5A AV Discrete IR Code (Input AV selection)
BF COMPONENT1 Discrete IR Code (Input COMPONENT1 selection)
D4 COMPONENT2 Discrete IR Code (Input COMPONENT2 selection)
D5 RGB PC Discrete IR Code (Input RGB PC selection)
D7 RGB DTV Discrete IR Code (Input RGB DTV selection)
C6 HDMI/DVI Discrete IR Code (Input HDMI/DVI selection)
79 ARC R/C Button
76 ARC (4:3) Discrete IR Code (only 4:3 mode)
77 ARC (16:9) Discrete IR Code (only 16:9 mode)
AF ARC (ZOOM) Discrete IR Code (only ZOOM1/ZOOM2 mode)
99 AUTO CONFIG Discrete IR Code

Data byte encoding

For commands with 2-byte data (e.g. kf volume, kg contrast, ku-style 2-byte values), the data is sent as a 2-character uppercase hex string. The "Real data mapping" examples in the source confirm the value is interpreted as a hex byte (e.g. 0x32 = decimal 50). Implementations should convert decimal step values to 2-char uppercase hex before transmission.

Source / hint observation

The input hint specified "TCP/IP", but the source document exclusively describes an RS-232 (UART) protocol. The Transport section above reflects the source. If the 50QNED74BAA also exposes a separate IP-based control protocol, that protocol would require its own source document.

Provenance

source_domains:
  - justaddpower.com
source_urls:
  - https://www.justaddpower.com/docs/manuals/rs232-lg.pdf
retrieved_at: 2026-06-02T01:30:16.492Z
last_checked_at: 2026-06-02T17:22:58.572Z

Verification Summary

verdict: verified
checked_at: 2026-06-02T17:22:58.572Z
matched_actions: 27
action_count: 27
confidence: medium
summary: "All 27 spec actions matched literally to source reference list with correct data ranges; transport parameters verified verbatim. (10 unresolved item(s) noted in Known Gaps.)"

Known Gaps

- "source is a generic LG RS-232 protocol reference; explicit applicability to the 50QNED74BAA model is not stated in the source."
- "no discrete settable parameters beyond the per-action data fields are documented in the source."
- "no unsolicited notification mechanism is described in the source."
- "no multi-step sequences are described in the source."
- "no safety warnings, interlock procedures, or power-on sequencing requirements are documented in the source."
- "source is a generic LG RS-232 protocol reference; explicit mapping to the 50QNED74BAA model is not stated in the source."
- "firmware version compatibility not stated in source."
- "voltage, current, or power-consumption specifications not stated in source."
- "fault behavior / error-recovery sequences not stated in source."
- "tile-mode value `11` (1×1) is not explicitly listed in the source table; only 00 and the 12-44 grid are documented."

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