Valcom v-9941a Service Manual

VSP-V-9941A

Issue 4

V-9941A ONE ZONE HANDSFREE TALKBACK CONTROL UNIT

INTRODUCTION

The V-9941A is a One Zone Handsfree Page Unit for use on an Electronic Key system line key position, a PABX loop start trunk port, a dedicated single line telephone or a 600 Ohm two-way page port with a contact closure.

These instructions contain the specifications and information necessary to install, operate and maintain the One Zone Handsfree Talkback Control Unit.

SPECIFICATIONS

Purpose

• Provides battery feed and loop detect circuitry to

properly interface with a telephone system C. O. position or dedicated single line telephone.

• Provides VOX circuit and handsfree amplifier to

drive 45 Ohm talkback speakers.

• Provides 600 Ohm input with ground start input

to operate on E-Key systems with a 600 Ohm two- way page port and a contact closure.

Applications

• PABX loop start trunk port

• Electronic key system C. O. Line position

• Telephone systems with 600 Ohm two-way page

port and contact closure

• Dedicated single line telephone

Refer to Figure 1 for a block diagram of a typical installation.

NOTE: When used with additional equipment, the V-9941A can also be accessed from a push-to-talk microphone for use in restaurant drive-in windows and other similar applications. Contact Valcom Application Engineering for information.

Features

• Loop start

• Input for ground start from a contact closure

• Provides optional battery feed

• Built in talkback amplifier

• Directly drives up to two talkback speakers

• Will drive Valcom one-way amplified speaker

assemblies

• Screw terminals for all connections

• Initial alert tone option

• Repeated alert tone option

• Music input

• Speaker inhibit option

• Operates on -24VDC "B" Battery

Limitations

• Maximum of two Valcom talkback speakers plus

40 one-way amplified speaker assemblies.

• Maximum allowable cable distance from control

unit to talkback speakers is 800 feet.

Capacity

• Each V-9941A will provide one zone of talkback

paging

• The V-9941A is a single talkpath unit

• Each V-9941A will drive up to two 45 Ohm

talkback speakers

• Up to 40 one-way amplified speaker assemblies

may be used in addition to the talkback speakers

1 947960

V-9941A

Electronic Key or PABX

Page Port Access (600 Ohms) with Contact Closure

C. O. Line Position or Loop Start Trunk Port

Figure 1 - Typical Loop Start Trunk Installation

Power Supply

Talkback Speaker

Dimensions/Weight

• 8.25" H x 4.65" W x 2.30" D (20.96cm H x 11.81cm W x 5.84cm D)

• 1.5 lbs. (0.68 kg)

Power Requirements

• 21.5 to -26VDC "B" Battery, 300mA maximum

Environment

Temperature: 0 to +50° C Humidity: 0 to 85% (non-precipitating)

SYSTEM DESIGN

General

The Valcom V-9941A talkback control unit is designed to provide paging access from a C. O. position or loop start trunk port of a telephone system. The V-9941A may also be connected to a 600 Ohm two-way page port with a contact closure or a dedicated single line telephone. The V-9941A contains all the VOX and handsfree amplifier circuitry required to drive up to two Valcom 45 Ohm talkback speakers.

Electronic Key, PABX Access or Dedicated Single Line Telephone

The following components are required when paging from a PABX loop start trunk port, Electronic Key System C. O. line position or a Dedicated Single Line Telephone:

A telephone system C. O. line port or PABX loop start trunk port with a circuit card installed or a dedicated single line telephone:

(1) V-9941A talkback control unit (1) VP-624B power supply 45 Ohm talkback speakers (maximum two)

The following components are required when paging from a 600 Ohm two-way paging port:

600 Ohm two-way paging port with contact closure (1) V-9941A talkback page control (1) VP-624B power supply 45 Ohm talkback speaker (maximum two)

Background Music

The V-9941A provides background music input and is designed to automatically cut off the music during a page. If background music is to be installed, a receiver providing an 8 Ohm output with 1-3 Watts of output power will be required.

Inhibit Option

The V-9941A is equipped with an inhibit lead that may be used in special applications to automatically turn off the speakers and allow a handset conversation between the calling party and a single line telephone connected to the paging Tip and Ring.

To use the inhibit function you will need a dedicated single line telephone modified for "A" Lead Control and a 5.1K Ohm 1/4 Watt resistor.

INSTALLATION

Mounting

Remove the metal mounting plate from the rear of the V-9941A enclosure. Using two #6 ¾ inch wood screws, mount the plate in a vacant space on the backboard with the telephone system common equipment. Both mounting holes must be utilized to insure secure mounting of the unit. See Figure 1A.

Open the V-9941A enclosure to access connections and option switches. Slide the rear of the unit (contains the board) onto the mounting plate and lock in place with screw provided. Make connections. Replace cover and lock in place with the #6 ¾ inch screw provided.

TO REMOVE COVER LOOSEN SCREW, THEN ACTIVATE LATCH

PLASTIC COVER

V-9941A

WIREWAY OPENING TO WALL PLATE AND JUNCTION BOX

CIRCUIT BOARD HOUSING ASSEMBLY

SNAP LATCH

FIGURE 1A

WIRE TIE LOOP WIRE TIE USED TO BUNDLE ENTERING AND LEAVING TERMINAL

METAL WALL MOUNTING PLATE

BRACKET LOCKING SCREW

.155 DIA. HOLES FOR MOUNTING SINGLE OR DOUBLE GANG JUNCTION HOLE PATTERN MATCHES BOTH AND US JUNCTION BOXES

1.5 x 2 WIRE ACCESS OPENING TO JUNCTION BOX

R T

SNAP LATCH FOR COVER

Music

Spkr

Inhibit

9 7

Spkr

Gnd Start

-24VDC

Ground

Ring

Tip

Ground (+)

-24VDC

C.O. Line Position or Loop Start Trunk Port

45 Ohm Talkback Speaker

ELECTRONIC KEY SYSTEM OR PABX ACCESS

INSTALLATION

WIRING INSTRUCTIONS:

__ b. "SW2" controls the repeated alert tone.

Place a check by each step as it is completed:

__ 1. Connect Tip of the telephone system trunk

position to the V-9941A terminal 1 (TIP).

__ 2. Connect Ring of the trunk port to the

__ c. "SW3" turn ON (Battery Feed Switch). __ 5. Plug in power supply.

NOTE: "A" battery may be substituted for "B"

V-9941A terminal 2 (RING).

__ 3. Connect Tip and Ring of the talkback

__ 6. Connect -24VDC "B" battery (may be

speakers to the V-9941A terminals 6 and 7 (SPKR) of the V-9941A.

4. Option Switches: __ a. "SW1" controls the initial alert tone. Turn

__ 7. Connect -24VDC "B" ground ("+" or "signal

the switch ON to precede each page with an

audible tone.

Turn the switch ON to have a short tone burst every 15 seconds during a handsfree page.

battery.

referred to as "-" or "signal battery") from power supply to terminal 4 (-24VDC) on the V-9941A.

ground") from power supply to terminal 3 (GND).

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