Motorola HKLN4604 Swivel Earpiece

What is the HKLN4604?

The Motorola HKLN4604 (also sold as HKLN4604A/B/C/D, and formerly the RLN6423) is a wired swivel earpiece with an integrated in-line microphone and push-to-talk (PTT) button, designed for use with Motorola two-way radios that use a 2-pin connector. It is compatible with the CLS, DTR, RDX, RM, XTN, DLR, and DTR600/700 series radios and is intended for hands-free, discreet communication during extended daily wear.

Specifications

Source: Motorola Solutions HKLN4604 Official Product Data Sheet (PDF)

What's in the Box

• 1× Motorola HKLN4604 swivel earpiece with in-line microphone and PTT button
• clothing clips (pre-attached to cable)

No radio, charging cable, or additional accessories are included.

Who This Product Is For

The HKLN4604 is designed for professional environments where staff need to communicate hands-free without a visible or bulky headset. Because the earpiece rests on top of the ear rather than inserting into the ear canal, it is practical in settings where multiple employees share the same radio.

Hospitality and hotels: Front desk staff, housekeeping supervisors, and event teams use this earpiece to coordinate discreetly in guest-facing areas. The low-profile design avoids the appearance of heavy tactical headsets.

Retail: Floor associates and loss prevention staff benefit from the clip-on PTT button, which allows quick communication without removing the radio from a belt clip or pocket.

Restaurants and food service: Kitchen-to-floor communication in busy restaurants requires lightweight, washable accessories that don't interfere with food handling. The over-ear design and dual clothing clips keep the cord secured during fast-paced service.

Education: School security coordinators and event staff at campuses use this earpiece for hallway monitoring and event management where a visible communication setup is acceptable but a full headset would be impractical.

Warehousing and light manufacturing: Workers operating on a floor with moderate ambient noise can use the earpiece to receive instructions from supervisors without stopping material handling tasks.

Security teams: Security personnel requiring a more discreet communication option than a speaker-mic — but without the cost or complexity of a surveillance-style earpiece — commonly use this model.

Car wash operations: Tunnel attendants and detail staff working with running equipment use this earpiece with CLS and RDX series radios to coordinate vehicle flow and processing stages.

Key Features

• Swivel earpiece rotates 180 degrees, allowing wear on either the left or right ear without repositioning the cable
• Over-ear (C-style hook) design; earpiece does not insert into the ear canal, making it sanitary for shared use
• In-line clip-on PTT button allows radio activation without accessing the radio body
• Integrated condenser microphone with omni-directional pickup and 100 Hz–10 kHz frequency range
• PVC-free cable construction; free of phthalates per European Chemicals Agency (ECHA) guidelines
• Ruggedized cable with two clothing clips for cord management during active use
• 2-pin slim connector compatible with a wide range of Motorola business radio series
• Lightweight rubber-molded earpiece at approximately 0.32 oz total weight
• Motorola tested and certified for use with compatible Motorola business radios
• Successive hardware revisions (A through D) reflect ongoing durability improvements; all variants are functionally equivalent

Radio Compatibility

The HKLN4604 uses Motorola's standard 2-pin connector and is compatible with the following radio series sold on techwholesale.com:

• Motorola CLS Series (CLS1110, CLS1410)
• Motorola DTR Series (DTR600, DTR700 and earlier DTR models)
• Motorola RDX Series
• Motorola RM Series
• Motorola DLR Series

For a broader confirmed compatibility list including older and legacy Motorola models (AXU4100, BC series, GP series, PR400, and others), refer to the official Motorola Solutions HKLN4604 product page.

Frequently Asked Questions

What radios is the Motorola HKLN4604 compatible with?

The HKLN4604 is compatible with Motorola two-way radios that use a standard 2-pin connector. Compatible series include the CLS, DTR, RDX, RM, XTN, DLR, and DTR600/700 series. It is also compatible with many older Motorola models including the CP series, GP series, BPR40, and others. Compatibility is determined by the 2-pin connector; if your radio uses a different connector style, the HKLN4604 will not connect without an adapter.

What is the difference between the HKLN4604 and the RLN6423?

The HKLN4604 is the direct replacement for the RLN6423. Both are the same product category — a 2-pin swivel earpiece with in-line microphone and PTT — but Motorola updated the part number when redesigning the accessory. All variant suffixes (HKLN4604A through HKLN4604D) represent incremental hardware revisions under Motorola's continued improvement process, not different products. If you used the RLN6423 previously, the HKLN4604 is the current equivalent.

Can the HKLN4604 be worn on either ear?

Yes. The earpiece uses a rotating swivel joint that allows it to be repositioned for either left-ear or right-ear wear. The cable and PTT button remain in the same position; only the earpiece hook is reoriented. No tools or modifications are required to switch sides.

Does the HKLN4604 sit inside the ear canal?

No. The HKLN4604 uses a C-style hook that positions the speaker over the ear opening without inserting into the ear canal. This over-ear placement is intentional — it reduces hygiene concerns in workplace settings where multiple staff members share the same radio and accessory. It also allows the user to maintain some ambient audio awareness.

Is the HKLN4604 PVC-free, and why does that matter?

Yes. The HKLN4604 cable and housing are manufactured without polyvinyl chloride (PVC) or phthalate plasticizers. Certain phthalates are classified as potential health hazards by the European Chemicals Agency (ECHA) and the California Office of Environmental Health Hazard Assessment (OEHHA). For workplaces with health, safety, or environmental compliance requirements — including healthcare facilities, food service operations, and school environments — the PVC-free construction may factor into accessory selection decisions.

What does the suffix letter (A, B, C, D) after HKLN4604 mean?

Motorola uses a letter suffix to denote successive hardware revisions under its continued improvement engineering process. HKLN4604A is the first revision, HKLN4604B the second, and so on. Each revision reflects incremental durability or manufacturing improvements. All suffix variants are functionally equivalent and compatible with the same radio series. The suffix does not indicate a different product or compatibility set.

How many clothing clips does the HKLN4604 include, and where do they attach?

The HKLN4604 includes two clothing clips that attach to the cable. They are used to route the cable along a shirt collar or chest, keeping it from dangling during active use. This is particularly useful for staff who move quickly — such as restaurant servers, warehouse workers, or security personnel — where a loose cable could snag on equipment or become a distraction.

What is the microphone frequency range of the HKLN4604?

According to the official Motorola Solutions product data sheet, the condenser microphone in the HKLN4604 has a frequency range of 100 Hz to 10 kHz with omni-directional pickup. This range is suitable for voice communication in typical business radio environments. The microphone sensitivity is –42 dB ±4 dB.

Related Products

• Motorola CLS Series Two-Way Radios — compatible radio series commonly paired with this earpiece
• Motorola DTR Series Radios — digital license-free radios compatible with the HKLN4604
• Motorola RDX Series Radios
• CLS Radio Accessories — additional accessories for the CLS series
• DTR Radio Accessories
• RDX Radio Accessories