Icom HM-138 Speaker/Microphone for M88 Transceiver User Manual

Introduction

This manual provides instructions for the proper use and maintenance of the Icom HM-138 Speaker/Microphone. The HM-138 is a waterproof speaker microphone designed for use with compatible Icom marine handheld transceivers, such as the M88. It allows for convenient communication without needing to hold the transceiver directly.

Figure 1: Icom HM-138 Speaker/Microphone. This image shows the front view of the speaker microphone, highlighting its compact design and the speaker grille.

Package Contents

Verify that the following items are included in the package:

HM-138 Speaker/Microphone unit
Alligator-type clip (pre-attached or separate)

Setup

Connecting to the Transceiver:
Ensure your Icom M88 transceiver is powered off. Locate the accessory jack on the side or top of the transceiver. Align the connector of the HM-138 speaker/microphone with the transceiver's accessory jack. Gently push the connector in until it clicks securely into place. Do not force the connection.
Securing the Speaker/Microphone:
Use the integrated alligator-type clip on the back of the HM-138 to attach it to your clothing, such as a lapel or shoulder strap, for convenient access and hands-free operation. Ensure the clip is firmly attached to prevent accidental detachment.
Waterproof Seal Check:
Before exposing the unit to water, ensure the connector is fully seated and the transceiver's accessory jack cover (if applicable) is properly closed around the cable to maintain the waterproof integrity of the system. The HM-138 itself is designed to be waterproof to JIS Grade 7 (1 meter for 30 minutes).

Operating Instructions

Powering On:
After connecting the HM-138, power on your Icom M88 transceiver as usual. The audio output will now be routed through the HM-138's speaker, and the microphone on the HM-138 will be active.
Receiving Audio:
Incoming transmissions will be heard through the speaker on the HM-138. Adjust the volume on your transceiver to a comfortable listening level.
Transmitting:
To transmit, press and hold the Push-To-Talk (PTT) button located on the side of the HM-138. Speak clearly into the microphone, which is typically located near the speaker grille. Release the PTT button to return to receive mode.
Emergency Button (if applicable):
If your transceiver and the HM-138 feature an emergency button, refer to your transceiver's manual for specific instructions on its use. Typically, this button activates an emergency signal or distress call.

Maintenance

Cleaning:
To clean the HM-138, wipe it with a soft, damp cloth. Do not use harsh chemicals, solvents, or abrasive cleaners, as these can damage the unit's finish and waterproof seals. For saltwater exposure, rinse thoroughly with fresh water and dry completely.
Waterproofing:
The HM-138 is waterproof to JIS Grade 7. This means it can withstand immersion in 1 meter of water for 30 minutes. However, ensure the connector is properly attached to the transceiver and the transceiver's seals are intact before exposing the unit to water. Do not intentionally submerge the unit beyond its rated depth or duration.
Storage:
Store the speaker/microphone in a cool, dry place away from direct sunlight and extreme temperatures when not in use. Avoid placing heavy objects on the unit.

Troubleshooting

Problem	Possible Cause	Solution
No audio from speaker/microphone.	Not properly connected. Transceiver volume too low. Transceiver not powered on.	Ensure connector is fully seated. Increase transceiver volume. Power on the transceiver.
Cannot transmit.	PTT button not pressed. Transceiver in receive mode. Faulty connection.	Press and hold PTT button firmly. Check transceiver's operating mode. Reconnect the speaker/microphone.
Distorted audio.	Volume too high. Microphone too close/far from mouth.	Adjust transceiver volume. Maintain optimal speaking distance (approx. 5-10 cm).

Specifications

Model Number: HM-138
Brand: ICOM
Connectivity Technology: Auxiliary
Special Feature: Clip
Compatible Devices: Icom M88 Transceiver (Speaker)
Included Components: Microphone
Polar Pattern: Unidirectional
Item Weight: 3.4 Ounces (approx. 96 grams)
Power Source: Corded Electric (via transceiver)
Signal-to-Noise Ratio: 76 dB
Waterproof Rating: JIS Grade 7 (1 meter for 30 minutes)
First Available Date: April 30, 2011

Warranty and Support

For warranty information and technical support, please refer to the documentation provided with your Icom M88 transceiver or visit the official Icom website. Contact Icom customer service directly for assistance with product defects or operational issues not covered in this manual.

Note: Unauthorized modifications or repairs to the HM-138 may void the product warranty and compromise its waterproof integrity.

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ICOM HM-138