Linear / Accessory reference

Linear ACT-21B

Linear ACT-21B: Miniature Linear custom block-coded MegaCode transmitter described for one device.

US source scopeUpdated 2026-09-12Independent Anderson reference

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Manufacturer identifier: ACT-21B. Keep every character when comparing it with your label or paperwork. A similar number does not establish the same component.

Denco supplier reference: RC ACP00615Product h1 and span.sku; Description: one-device MegaCode, custom block and lot quantity · checked 2026-09-12 · Denco

Values apply to the exact identifier and scope in the cited source.
Supplier-stated detail	Miniature Linear custom block-coded MegaCode transmitter described for one device. Denco supplier reference: RC ACP00615Product h1 and span.sku; Description: one-device MegaCode, custom block and lot quantity · checked 2026-09-12 · Denco
Supplier-stated detail	The supplier lists ten-unit lots. Denco supplier reference: RC ACP00615Product h1 and span.sku; Description: one-device MegaCode, custom block and lot quantity · checked 2026-09-12 · Denco
Selection limitation	One-device capacity does not establish button count. Exact frequency and receiver models are unspecified, and no equivalence to ACT-31B is stated. Denco supplier reference: RC ACP00615Product h1 and span.sku; Description: one-device MegaCode, custom block and lot quantity · checked 2026-09-12 · Denco

Documented fitment & exclusions

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A component pairing applies only to the listed items and source conditions. It does not establish suitability for an installed opener or compatibility through another component.

Source statements and their exact conditions. Use the checker below to compare equipment or a component.
Equipment or component / relationship	Evidence and conditions
MDR/U Documented compatibility From ACT-21B to MDR/U.	Conditional Additional source conditions or an adapter must be checked before confirming compatibility. Details still needed connection-purpose source conditions Use the exact label and the source scope below. An unanswered condition keeps this result conditional or unverified. Denco group scope and separately reviewed membership associate ACT-21B with MDR/U for the stated function. Applies only within this source scope Market: US connection-purpose: MegaCode radio reception by MDR/U; exact code enrollment must be checked. Bounded Denco supplier group association; verify the stated configuration. No physical or human engineering certification. This association concerns the external receiver. Nearly any opener is not universal downstream fitment; confirm the receiver input, power, installation and programming requirements. Custom block-coded and ordinary transmitter variants remain separate; no lot quantity or button count creates extra pairings. Denco supplier reference: RC DNR00100h1; span.sku; Description first bullet: explicit MDR/U designation, channel/type and Linear MegaCode transmitter scope; Description second connection bullet · checked 2026-09-12 · Denco Denco supplier reference: RC ACP00615Product h1 and span.sku; Description: one-device MegaCode, custom block and lot quantity · checked 2026-09-12 · Denco

Direct replacement paths

No direct successor for ACT-21B is verified in this reference.

A direct replacement statement does not establish reverse interchangeability, a kit equivalent or a later replacement chain.

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Selected: ACT-21B · Read its reference. Selection identifies a record; it does not confirm fitment.

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Sources & scope

Denco supplier reference: RC DNR00100Denco · US · checked 2026-09-12
Denco supplier reference: RC ACP00615Denco · US · checked 2026-09-12

Anderson prepared this reference from the listed evidence. Source statements are not an Anderson installation inspection or independent product test. Official documents stay on their publisher’s website.

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