Middle Atlantic RLNK-Select control commands

Summary

The Middle Atlantic RackLink (RLNK) Series is a family of rack power products (Select, Premium, Premium+) that expose a binary control protocol over RS-232 (Premium only) and TCP/IP port 60000. Every frame is a fixed hex envelope: 0xFE <length> <data envelope> <checksum> 0xFF, where the checksum is the 7-bit-masked sum of all bytes from the header through the end of the data envelope. A Login command (user|password by default) is required before any other command will be honored, and the device sends periodic Ping frames that the controller must answer or be disconnected after three misses.

Transport

protocols:
  - tcp
  - serial
addressing:
  port: 60000
serial:
  baud_rate: 9600
  data_bits: 8
  parity: none
  stop_bits: 1
  flow_control: none
auth:
  type: password  # protocol-specific Login command carries "Username|Password" (default "user|password")

Frame format (all transports): 0xFE <length> <data envelope> <checksum> 0xFF

0xFE = Header
<length> = 1 byte = total bytes in data envelope
<data envelope> = 3–250 bytes, always begins with a 0x00 prefix byte, then command + subcommand + payload
<checksum> = (sum of all bytes from 0xFE through end of data envelope) & 0x7F
0xFF = Tail

Reserved/protected bytes 0xFE, 0xFF, 0xFD inside the data envelope must be escaped with 0xFD + inverted value; the escape byte is excluded from length and checksum calculations.

Traits

- powerable       # inferred from outlet on/off and cycle commands
- queryable       # inferred from get-state, get-count, sensor, and log read commands
- routable        # inferred from power sequencing (sequence up / sequence down) commands

Actions

# ----- Session / link management -----
- id: ping
  label: Ping
  kind: action
  command: "FE 03 00 01 01 {checksum} FF"
  notes: |
    Device periodically sends this to the controller; controller must respond with Pong or
    be considered disconnected after three unanswered pings. Checksum always 0x03.
  params: []

- id: pong
  label: Ping Response
  kind: action
  command: "FE 03 00 01 10 {checksum} FF"
  notes: Response to a device-initiated Ping. Checksum always 0x12.
  params: []

- id: login
  label: Login
  kind: action
  command: "FE {length} 00 02 01 {credentials} {checksum} FF"
  notes: |
    Credentials encoded as ASCII "Username|Password". Default "user|password"
    (hex 75 73 65 72 7C 70 61 73 73 77 6F 72 64). Must be sent before any other command.
    On Premium+ the login username/password may reference any admin user with the control
    protocol enabled (no default "user" account).
  params:
    - name: credentials
      type: string
      description: ASCII string "Username|Password"

# ----- NACK (device-to-controller error response, not a controller-sent command) -----
# Documented for completeness; no action is sent by the controller.
# Error codes: 0x01 Bad CRC, 0x02 Bad Length, 0x03 Bad Escape, 0x04 Invalid command,
# 0x05 Invalid sub-command, 0x06 Wrong byte count, 0x07 Invalid data bytes,
# 0x08 Invalid Credentials, 0x10 Unknown Error, 0x11 Access Denied (EPO).

# ----- Outlets (0x20) and Dry Contacts (0x30) -----
- id: read_outlet_status
  label: Read Outlet Status
  kind: query
  command: "FE 04 00 20 02 {outlet} {checksum} FF"
  params:
    - name: outlet
      type: integer
      description: Outlet number 1-16 (0x01-0x10)

- id: read_contact_status
  label: Read Dry Contact Status
  kind: query
  command: "FE 04 00 30 02 {contact} {checksum} FF"
  params:
    - name: contact
      type: integer
      description: Dry contact number 1-8 (0x01-0x08)

- id: write_outlet_status
  label: Write Outlet State
  kind: action
  command: "FE 09 00 20 01 {outlet} {state} {cycle_time} {checksum} FF"
  params:
    - name: outlet
      type: integer
      description: Outlet number 1-16
    - name: state
      type: enum
      values: [off, on, cycle, not_controllable]
      description: "0x00 OFF, 0x01 ON, 0x02 Cycle (uses cycle_time), 0x03 Not Controllable (response only)"
    - name: cycle_time
      type: string
      description: ASCII 4 digits, 0000-3600 seconds; send 0x30 0x30 0x30 0x30 ("0000") for on/off

- id: write_contact_status
  label: Write Dry Contact State
  kind: action
  command: "FE 09 00 30 01 {contact} {state} {cycle_time} {checksum} FF"
  params:
    - name: contact
      type: integer
      description: Dry contact number 1-8
    - name: state
      type: enum
      values: [off, on, cycle]
      description: "0x00 OFF, 0x01 ON, 0x02 Cycle"
    - name: cycle_time
      type: string
      description: ASCII 4 digits, 0000-3600 seconds; send 0x30 0x30 0x30 0x30 ("0000") for on/off

# ----- Outlet (0x21) and Dry Contact (0x31) Names -----
- id: read_outlet_name
  label: Read Outlet Name
  kind: query
  command: "FE 04 00 21 02 {outlet} {checksum} FF"
  params:
    - name: outlet
      type: integer
      description: Outlet number 1-16

- id: write_outlet_name
  label: Write Outlet Name
  kind: action
  command: "FE {length} 00 21 01 {outlet} {name} {checksum} FF"
  params:
    - name: outlet
      type: integer
      description: Outlet number 1-16
    - name: name
      type: string
      description: ASCII name string

- id: read_contact_name
  label: Read Dry Contact Name
  kind: query
  command: "FE 04 00 31 02 {contact} {checksum} FF"
  params:
    - name: contact
      type: integer
      description: Dry contact number 1-8

- id: write_contact_name
  label: Write Dry Contact Name
  kind: action
  command: "FE {length} 00 31 01 {contact} {name} {checksum} FF"
  params:
    - name: contact
      type: integer
      description: Dry contact number 1-8
    - name: name
      type: string
      description: ASCII name string

# ----- Outlet (0x22) and Dry Contact (0x32) Counts -----
- id: read_outlet_count
  label: Read Outlet Count
  kind: query
  command: "FE 03 00 22 02 25 FF"
  notes: Checksum always 0x25; tail always 0xFF. No variable params.
  params: []

- id: read_contact_count
  label: Read Dry Contact Count
  kind: query
  command: "FE 03 00 32 02 35 FF"
  notes: Checksum always 0x35; tail always 0xFF. No variable params.
  params: []

# ----- Power Sequencing (0x36) -----
- id: sequence_outlets
  label: Power Sequence
  kind: action
  command: "FE 08 00 36 01 {direction} {delay} {checksum} FF"
  notes: |
    Premium+ ignores the delay field and uses its configured per-outlet delay (send
    0x30 0x30 0x30 0x30 "0000"). Non-Premium+: delay 0000-0999 seconds ASCII.
  params:
    - name: direction
      type: enum
      values: [up, down]
      description: "0x01 Sequence Up, 0x03 Sequence Down"
    - name: delay
      type: string
      description: ASCII 4 digits, 0000-0999 seconds

# ----- Energy Management (0x23, Premium/Premium+ only) -----
- id: set_outlet_energy_state
  label: Set Outlet Energy State
  kind: action
  command: "FE 05 00 23 01 {outlet} {state} {checksum} FF"
  notes: Premium/Premium+ only.
  params:
    - name: outlet
      type: integer
      description: Outlet number 1-16
    - name: state
      type: enum
      values: [disconnected, standby, on, off, unknown]
      description: |
        ASCII letter: 0x44 D, 0x53 S, 0x49 I (ON), 0x4F O (OFF), 0x55 U (Unknown)

- id: get_outlet_energy_state
  label: Get Outlet Energy State
  kind: query
  command: "FE 04 00 23 02 {outlet} {checksum} FF"
  notes: Premium/Premium+ only.
  params:
    - name: outlet
      type: integer
      description: Outlet number 1-16

# ----- Emergency Power Off (0x37) -----
- id: epo
  label: Emergency Power Off
  kind: action
  command: "FE 04 00 37 01 {action} {checksum} FF"
  safety: critical
  notes: |
    EPO Initiate (0x01) cuts outlet power. EPO Recover (0x00) restores operation.
    NACK code 0x11 "Access Denied (EPO)" indicates an active EPO.
  params:
    - name: action
      type: enum
      values: [recover, initiate]
      description: "0x00 EPO Recover, 0x01 EPO Initiate"

# ----- Log Alerts Registration (0x40) -----
- id: get_log_alerts
  label: Get Log Alert Registration
  kind: query
  command: "FE 03 00 40 02 {checksum} FF"
  params: []

- id: set_log_alerts
  label: Set Log Alert Registration
  kind: action
  command: "FE 05 00 40 01 {byte1} {byte2} {checksum} FF"
  notes: |
    Two-bitfield bytes. Byte 1: bit1 Normal, bit2 OverV, bit3 UnderV, bit4 OverTemp,
    bit5 UnderTemp, bit6 Surge. Byte 2: bit1 AutoPing, bit2 RS232Ping, bit3 OverI,
    bit4 UnderI, bit5 EPO.
  params:
    - name: byte1
      type: integer
      description: Bitfield byte 1
    - name: byte2
      type: integer
      description: Bitfield byte 2

# ----- Status Change Registration (0x41) -----
- id: get_status_change_registration
  label: Get Status Change Registration
  kind: query
  command: "FE 03 00 41 02 {checksum} FF"
  params: []

- id: set_status_change_registration
  label: Set Status Change Registration
  kind: action
  command: "FE 06 00 41 01 {b1} {b2} {b3} {b4} {checksum} FF"
  notes: |
    Four-bitfield bytes. See source for per-bit meanings (outlet/contact/EPO/sequence/
    threshold/sensor change enable bits).
  params:
    - name: b1
      type: integer
      description: Bitfield byte 1
    - name: b2
      type: integer
      description: Bitfield byte 2
    - name: b3
      type: integer
      description: Bitfield byte 3
    - name: b4
      type: integer
      description: Bitfield byte 4

# ----- Sensor Values (0x50-0x61) -----
- id: get_kilowatt_hours
  label: Get Kilowatt Hours
  kind: query
  command: "FE 03 00 50 02 {checksum} FF"
  notes: Response value format "##########.#" (10 integer + 1 decimal digits).
  params: []

- id: get_peak_voltage
  label: Get Peak Voltage
  kind: query
  command: "FE 03 00 51 02 {checksum} FF"
  notes: Response format "###".
  params: []

- id: get_rms_voltage
  label: Get RMS Voltage
  kind: query
  command: "FE 03 00 52 02 {checksum} FF"
  notes: Response format "###".
  params: []

- id: get_peak_load
  label: Get Peak Load
  kind: query
  command: "FE 03 00 53 02 {checksum} FF"
  notes: Response format "##.#".
  params: []

- id: get_rms_load
  label: Get RMS Load
  kind: query
  command: "FE 03 00 54 02 {checksum} FF"
  notes: Response format "##.#".
  params: []

- id: get_temperature
  label: Get Temperature
  kind: query
  command: "FE 03 00 55 02 {checksum} FF"
  notes: Response format "###" (Fahrenheit).
  params: []

- id: get_wattage
  label: Get Wattage
  kind: query
  command: "FE 03 00 56 02 {checksum} FF"
  notes: Response format "####".
  params: []

- id: get_power_factor
  label: Get Power Factor
  kind: query
  command: "FE 03 00 57 02 {checksum} FF"
  notes: Response format "#.#".
  params: []

- id: get_thermal_load
  label: Get Thermal Load (BTU)
  kind: query
  command: "FE 03 00 58 02 {checksum} FF"
  notes: Response format "####.#".
  params: []

- id: get_surge_protection_state
  label: Get Surge Protection State
  kind: query
  command: "FE 03 00 59 02 {checksum} FF"
  notes: "Response: 0x00 n/a, 0x01 protected, 0x02 compromised."
  params: []

- id: get_energy_management_state
  label: Get Energy Management State (all outlets)
  kind: query
  command: "FE 03 00 60 02 {checksum} FF"
  notes: 16 ASCII letters, one per outlet (D/S/I/O/U).
  params: []

- id: get_occupancy_state
  label: Get Occupancy State
  kind: query
  command: "FE 03 00 61 02 {checksum} FF"
  notes: "Response: 0x55 'U' Unoccupied, 0x4F 'O' Occupied."
  params: []

# ----- Thresholds (0x70-0x77) -----
- id: get_low_voltage_threshold
  label: Get Low Voltage Threshold
  kind: query
  command: "FE 03 00 70 02 {checksum} FF"
  params: []

- id: set_low_voltage_threshold
  label: Set Low Voltage Threshold
  kind: action
  command: "FE {length} 00 70 01 {value} {checksum} FF"
  params:
    - name: value
      type: string
      description: ASCII "###"

- id: get_high_voltage_threshold
  label: Get High Voltage Threshold
  kind: query
  command: "FE 03 00 71 02 {checksum} FF"
  params: []

- id: set_high_voltage_threshold
  label: Set High Voltage Threshold
  kind: action
  command: "FE {length} 00 71 01 {value} {checksum} FF"
  params:
    - name: value
      type: string
      description: ASCII "###"

- id: get_max_load_current
  label: Get Max Load Current
  kind: query
  command: "FE 03 00 73 02 {checksum} FF"
  params: []

- id: set_max_load_current
  label: Set Max Load Current
  kind: action
  command: "FE {length} 00 73 01 {value} {checksum} FF"
  params:
    - name: value
      type: string
      description: ASCII "##.#"

- id: get_min_load_current
  label: Get Min Load Current
  kind: query
  command: "FE 03 00 74 02 {checksum} FF"
  params: []

- id: set_min_load_current
  label: Set Min Load Current
  kind: action
  command: "FE {length} 00 74 01 {value} {checksum} FF"
  params:
    - name: value
      type: string
      description: ASCII "##.#"

- id: get_max_temperature
  label: Get Max Temperature
  kind: query
  command: "FE 03 00 76 02 {checksum} FF"
  params: []

- id: set_max_temperature
  label: Set Max Temperature
  kind: action
  command: "FE {length} 00 76 01 {value} {checksum} FF"
  params:
    - name: value
      type: string
      description: ASCII "###"

- id: get_min_temperature
  label: Get Min Temperature
  kind: query
  command: "FE 03 00 77 02 {checksum} FF"
  params: []

- id: set_min_temperature
  label: Set Min Temperature
  kind: action
  command: "FE {length} 00 77 01 {value} {checksum} FF"
  params:
    - name: value
      type: string
      description: ASCII "###"

# ----- Log read / count / clear (0x80-0x82) -----
- id: read_log_entries
  label: Read Log Entries
  kind: query
  command: "FE 0A 00 80 02 {start_idx} 7C {count} {checksum} FF"
  notes: |
    start_idx is ASCII 4 digits ("0002" = entry 2). count is ASCII 2 digits ("10" = 10).
    Separator 0x7C = "|". Response is one frame per entry.
  params:
    - name: start_idx
      type: string
      description: ASCII 4-digit starting index
    - name: count
      type: string
      description: ASCII 2-digit entry count

- id: get_log_count
  label: Get Log Count
  kind: query
  command: "FE 03 00 81 02 {checksum} FF"
  notes: Response data is ASCII 4-digit count (e.g. "0120" = 120).
  params: []

- id: clear_log
  label: Clear Log
  kind: action
  command: "FE 03 00 82 01 {checksum} FF"
  params: []

# ----- Product info (0x90, 0x91, 0x93, 0x94, 0x95) -----
- id: get_part_number
  label: Get Part Number
  kind: query
  command: "FE 03 00 90 02 {checksum} FF"
  notes: Response: ASCII string up to 50 characters.
  params: []

- id: get_amp_hour_rating
  label: Get Amp Hour Rating
  kind: query
  command: "FE 03 00 91 02 {checksum} FF"
  notes: Response format "###".
  params: []

- id: get_surge_existence
  label: Get Surge Existence
  kind: query
  command: "FE 03 00 93 02 {checksum} FF"
  notes: 'Response: "Y" or "N".'
  params: []

- id: get_ip_address
  label: Get Current IP Address
  kind: query
  command: "FE 03 00 94 02 {checksum} FF"
  notes: Response: ASCII IPv4 "###.###.###.###" (no leading zeroes, variable length).
  params: []

- id: get_mac_address
  label: Get MAC Address
  kind: query
  command: "FE 03 00 95 02 {checksum} FF"
  notes: Response: ASCII "##:##:##:##:##:##".
  params: []

Feedbacks

- id: outlet_state
  type: enum
  values: [off, on, not_controllable]
  description: Per-outlet state (0x20/0x30 response/status, subcommand 0x10/0x12/0x30)

- id: contact_state
  type: enum
  values: [off, on]
  description: Per-dry-contact state

- id: outlet_controllable_mask
  type: string
  description: 16-byte mask (0x22 response): "C" controllable, "N" not-controllable, "X" absent

- id: contact_controllable_mask
  type: string
  description: 8-byte mask (0x32 response)

- id: sequence_state
  type: enum
  values: [idle, sequencing_up, sequencing_up_complete, sequencing_down, sequencing_down_complete]
  description: 0x36 response; 0x00 idle/fallback, 0x01 up, 0x02 up-complete, 0x03 down, 0x04 down-complete

- id: energy_state
  type: enum
  values: [disconnected, standby, on, off, unknown]
  description: 0x23 response: D/S/I/O/U

- id: epo_state
  type: enum
  values: [normal, epo_mode]
  description: 0x37 response: 0x00 normal, 0x01 EPO mode

- id: surge_state
  type: enum
  values: [n_a, protected, compromised]
  description: 0x59 response

- id: occupancy_state
  type: enum
  values: [unoccupied, occupied]
  description: 0x61 response

- id: login_result
  type: enum
  values: [rejected, accepted]
  description: 0x02 response: 0x00 rejected, 0x01 accepted

- id: nack_code
  type: integer
  description: |
    Error code from NACK (0x10): 0x01 BadCRC, 0x02 BadLength, 0x03 BadEscape,
    0x04 InvalidCmd, 0x05 InvalidSub, 0x06 BadByteCount, 0x07 BadDataBytes,
    0x08 InvalidCreds, 0x10 UnknownError, 0x11 AccessDeniedEPO

Variables

- name: outlet_name
  type: string
  description: Per-outlet label (1-16), writable via 0x21 set

- name: contact_name
  type: string
  description: Per-dry-contact label (1-8), writable via 0x31 set

- name: low_voltage_threshold
  type: string
  description: ASCII "###"; 0x70

- name: high_voltage_threshold
  type: string
  description: ASCII "###"; 0x71

- name: max_load_current
  type: string
  description: ASCII "##.#"; 0x73

- name: min_load_current
  type: string
  description: ASCII "##.#"; 0x74

- name: max_temperature
  type: string
  description: ASCII "###"; 0x76

- name: min_temperature
  type: string
  description: ASCII "###"; 0x77

Events

- id: outlet_status_change
  description: 0x20/0x30 response with subcommand 0x12 (status update) - pushed on local change. Requires bit 1 of Register Status Change byte 1 to be enabled.

- id: outlet_log_update
  description: 0x20/0x30 response with subcommand 0x30 (scheduled log report).

- id: status_change
  description: 0x23 response with subcommand 0x12 (status change, Premium/Premium+).

- id: epo_status_change
  description: 0x37 response with subcommand 0x12 (EPO state changed).

- id: sensor_status_change
  description: Sensor (0x50-0x61) response with subcommand 0x12; requires the corresponding bit in Register Status Change bytes 5-6 to be enabled.

- id: threshold_status_change
  description: Threshold (0x70-0x77) response with subcommand 0x12.

- id: log_entry
  description: 0x80 multi-frame response carrying one log record each.

- id: log_alert
  description: 0x40 unsolicited alert; requires the corresponding bit in Register Log Alerts bytes 1-2 to be enabled.

Macros

- id: sequence_up
  description: 0x36 direction 0x01 - bring outlets on in configured order with delay between each
  steps:
    - send: sequence_outlets
      params: {direction: up, delay: "<configured seconds 0000-0999>"}

- id: sequence_down
  description: 0x36 direction 0x03 - turn outlets off in configured order
  steps:
    - send: sequence_outlets
      params: {direction: down, delay: "<configured seconds 0000-0999>"}

- id: login_and_pong
  description: Required session establishment sequence
  steps:
    - send: login
      params: {credentials: "user|password"}
    - wait: device-initiated ping
    - send: pong

Safety

confirmation_required_for:
  - epo  # EPO Initiate cuts outlet power; NACK 0x11 blocks other commands until EPO Recover
interlocks:
  - "EPO active blocks all commands except EPO Recover (NACK 0x11 Access Denied)"
  - "Login must be re-established after three missed pings; device enters disconnected state and NACKs subsequent commands"

Notes

Frame construction: every command must be assembled per the frame format. length = bytes in the data envelope (between the length byte and the checksum, inclusive of the leading 0x00 prefix). checksum = (sum of bytes from 0xFE through end of data envelope) & 0x7F. Escape any 0xFE/0xFF/0xFD inside the data envelope with 0xFD + inverted value; the escape byte is excluded from length and checksum.
Model variants:
- Select: TCP/IP only. Default user/password login is enabled by first web login.
- Premium: RS-232 and TCP/IP. Default user/password login enabled by first web login.
- Premium+: TCP/IP. No default user account; login username/password must reference any admin account with the control protocol checkbox enabled. Energy management and sensor/threshold features are Premium/Premium+ only.
Subcommand semantics: in responses, subcommand 0x10 is the reply to a controller command, 0x12 is an unsolicited status update, 0x30 is a log report. 0x01 is always the SET/WRITE form and 0x02 is always the GET/READ form.
Cycle time encoding: cycle time fields are 4 ASCII digits, not binary, even though the rest of the protocol is binary hex. The decimal point is part of the ASCII string for sensor/threshold values that include one.
Ping policy: pings are device-initiated. Three unanswered pings → connection considered lost; controller must re-login to resume.

Provenance

source_domains:
  - res.cloudinary.com
  - digitalautomation.us
  - files.d-tools.com
  - markertek.com
  - files.avprosupply.com
source_urls:
  - "https://res.cloudinary.com/avd/image/upload/v1598618818/Resources/Middle%20Atlantic/Power/Firmware/I-00472-Series-Protocol.pdf"
  - https://digitalautomation.us/wp-content/uploads/2023/09/MiddleAtlantic_RacklinkSelect_IP.pdf
  - "http://files.d-tools.com/Visualizations/Approved/Middle%20Atlantic/Documents/Middle%20Atlantic_RLNK-915R_Manual1.PDF"
  - "https://www.markertek.com/Attachments/Manuals/MIDDLE%20ATLANTIC/RLNK-215-Manual.pdf"
  - https://files.avprosupply.com/files/attachments/13508/middle-atlantic-rlnk-215-manual.pdf
retrieved_at: 2026-05-27T02:31:54.772Z
last_checked_at: 2026-06-02T17:23:32.036Z

Verification Summary

verdict: verified
checked_at: 2026-06-02T17:23:32.036Z
matched_actions: 53
action_count: 53
confidence: medium
summary: "All 53 spec actions match source commands with correct opcodes, parameters, and transport details; full catalogue coverage. (2 unresolved item(s) noted in Known Gaps.)"

Known Gaps

- "per-model command capability matrix is partially stated (e.g. RS-232 only on Premium, energy management only on Premium/Premium+); firmware revisions and per-firmware command gating are not stated."
- "per-firmware-version command gating is not stated; voltage/current/power ratings are not stated; physical pinout of the RS-232 DB connector is not stated; default delay values for sequencing are not stated."

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

Middle Atlantic RackLink Series Control Spec

Compatible models