Shure 888TT Adjustments, Operation, Replacement Parts, Furnished Accessory, Optional Accessory

Microphone connector wiring is shown in the table below.

Microphone Connector Wiring

Pin	Color	Function	Pin	Color	Function
1		N.C.	5	Black	PTT
					Switch
					Ground
2	White	Dc Bias (+),	6	Red	Audio Out
		Audio Out			(Ac
					coupled)
3	Yellow	PTT Switch	7	Drain	Ground
4	Blue	NC	8		N.C.

The ALM-88 cable is wired at the microphone connector as shown in Figure 3 at the bottom of the page.

ADJUSTMENTS

Operation of microphone and DTMF functions requires that the 888TT be connected to the communications equip- ment and that the equipment power is turned on.

After connection to the communications set, turn the equipment power On. Power application can be verified by pressing the push-to-talk switch and observing the keypad LED backlighting.

Factory preset microphone audio and DTMF levels are correct for aircraft radios with standard input circuits (as defined in RTCA DO-170), and level adjustment should not ordinarily be necessary. When such adjustment is neces- sary, it should be performed only by Shure Brothers Inc. or by an FAA Approved Service Facility. Use the supplied screwdriver to adjust the microphone sensitivity and DTMF output levels as follows:

1.Microphone sensitivity: Press the push-to-talk but- ton and speak normally into the microphone while checking transmitter modulation. Adjust the micro- phone sensitivity control (case back, hole ªBº in Figure 4) and repeat the talk test as required.

DTMF LEVEL

ADJUST (C)

MICROPHONE

SENSITIVITY

ADJUST (B)

CABLE

RELEASE (A)

MICROPHONE CASE BACK

FIGURE 4

2.DTMF output: Press and hold the push-to-talk button. Depress and hold down a keypad button for a continu- ous tone. Adjust the DTMF output control (case back, hole ªCº in Figure 4) as required.

OPERATION

Voice Transmission

1.Hold the microphone comfortably in the hand posi- tioned so that the Top-Talk Sound ChannelsTM at the top of the case are near the mouth. The clearest sound is often obtained with the microphone at the corner of the mouth, with the cable away from the face.

2.Depress the push-to-talk button and make sure the equipment is in the transmit mode before speaking.

Dialing

1.Press and hold the push-to-talk button.

2.Press the desired keypad buttons in sequence. A high- pitched tone will confirm that the code has been trans- mitted. (The microphone audio is muted during DTMF tone transmission.)

REPLACEMENT PARTS

Modular plug-cable with PJ-068 plug assembly . . ALM-88

FURNISHED ACCESSORY

Screwdriver . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 65A1587

OPTIONAL ACCESSORY

Mounting Bracket (3 in kit) . . . . . . . . . . . . . . . . . . RK6MB

RED

WHITE

RED

NC

NC

WHITE

SLEEVE (GROUND)

RING (AUDIO)

TIP (PTT)

PJ-068 CONNECTOR (TO RADIO)

RJ11 CONNECTOR (TO MICROPHONE)

MODULINK CABLE WIRING

FIGURE 3

3