What is the purpose of the Shure earphone accessory cable model CBL-M-K?
In 2010, Shure introduced new SE series earphones. A key feature on each model is a replaceable cable that has sub-miniature MMCX connectors: a female connector on each earphone and two male connectors on cable.
The model CBL-M-K is a 56 inch (142 cm) replacement cable that includes one-button remote switch and microphone. The earphones then serve a dual purpose: to listen to music or to listen to the person on the other end of the call. The microphone is used to speak to the other person during a call.
NOTE 1: The CBL-M-K cable is not intended for Apple products.
The switch is actuated to SEND a new phone call or to END an existing phone call. When actuated, the switch shorts the mic signal line to ground. Typically, this action is interpreted by the phone as a SEND call or an END call function.
NOTE 2: It is the design of the phone/mobile device that determines what happens with this switch is actuated. The type of function is not determined by the CBL-M-K switch. Check with the phone/mobile device manufacturer to determine if the CBL cable will provide the functions desired.
The 3.5mm male plug is configured as follows:
Tip - audio feed to left earphone;
Ring 1 - audio feed to right earphone;
Ring 2 - ground return for earphones and for microphone;
Sleeve - audio feed from microphone.
The operating voltage range for the microphone is 1.5Vdc to 3.6Vdc. The current draw is 0.25 mA maximum. The impedance is 300 ohms. The output level is -52dBV at 1kHz, 94 dB SPL.
The diameter of the CBL-M-K cable, measured at 5 inches below the earphone, is 0.060 inch. At the 3.5mm plug, the cable diameter is 0.090 inch. The cable on the CBL-M-K is slightly more flexible than the SE earphone cable.
At the 3.5 mm phone plug, the round, plastic "shoulder" (that secures the metal portion of the plug) has a diameter of 0.29" - 19/64".