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HANDS-FREE
SPEAKERPHONE-
Ramsey Electronics Model No.
How many times have you played acrobat juggling the phone
on your shoulder while looking up something or while working at
the bench? And, wouldn't it be nice to be able to answer a call
from anywhere in your shop or garage? This handy
Speakerphone will do the trick and doubles as a hands-free
intercom too!
•
Completely Hands-free; talk and listen at will
•
Needs no battery - runs off the phone line
•
Sensitive pick up throughout the room
•
Excellent speaker volume
•
Doubles as a hands-free intercom too! Connect as many units as
desired across 2 conductor wire
•
Informative manual answers questions on theory, hook-ups and
uses - enhances resale value too!
•
Includes our case for a finished 'Pro' look.
•
Clear, concise assembly instructions carefully guide you to a
finished kit that works FIRST time!
INTERCOM KIT
SP1
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Table of Contents
Summary of Contents for Ramsey Electronics SP1
- Page 1 HANDS-FREE SPEAKERPHONE- INTERCOM KIT Ramsey Electronics Model No. How many times have you played acrobat juggling the phone on your shoulder while looking up something or while working at the bench? And, wouldn’t it be nice to be able to answer a call...
- Page 2 Ramsey Electronics publication No. SP1 Revision E First printing: January 1995 COPYRIGHT 1994 by Ramsey Electronics, Inc. 590 Fishers Station Drive, Victor, New York 14564. All rights reserved. No portion of this publication may be copied or duplicated without the written permission of Ramsey Electronics, Inc.
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Page 3: Table Of Contents
AND INSTRUCTION MANUAL FOR SP1 HANDS-FREE SPEAKERPHONE- INTERCOM KIT TABLE OF CONTENTS Introduction to the SP1....4 Parts list for the SP1 ...... 5 Parts layout diagram ...... 6 Assembly instructions..... 7 Schematic diagram....... 12 Initial testing........15 Optimizing your set-up ....16 Understanding Speakerphones.. -
Page 4: Introduction To The Sp1
The Ramsey SP1 Speakerphone PC board and circuit design are solid, rugged applications of today's IC-based telephoning technology. You may wish to read ahead and learn how to use the SP1 and how it works before beginning actual kit construction. Build and learn about the Ramsey... -
Page 5: Parts List For The Sp1
PARTS SUPPLIED WITH SP1 KIT CAPACITORS 100 pF disc [marked 100 or 101] (C1) .01 uF disc [marked .01, 103 or 10nf ] (C9,10,13,14) .05 or .047 uF disc [marked .047 or 473 or .05 or 503] (C3, C18) .1 uF disc [marked .1 or 104] (C28) .47 uF electrolytic (C2,C4,C6,C7,C8,C17,C22,C23) -
Page 6: Sp-1 Parts Layout Diagram
SP-1 PARTS LAYOUT DIAGRAM SP-1 • 6... -
Page 7: Assembly Instructions
The part is then soldered securely to the board, and the remaining lead length is clipped off. SP1 ASSEMBLY INSTRUCTIONS: We have a twofold "strategy" for the order of the following kit assembly steps. First, we install parts in physical relationship to each other, so there's minimal chance of inserting wires into wrong holes. - Page 8 PC board position easily. Notice that the tab nearest to the edge of the board is connected to the common ground of the circuit. The other two tabs are connected together to the SP1's speaker audio output. You have a choice of installing J1 supplied or your own speaker wire, depending on your intended application.
- Page 9 D5 (small gray body with black band). The banded end marks the cathode and must be oriented as illustrated. B) If you plan to use your SP1 only as a duplex intercom, do not install D5. Place it in a safe place for possible future use.
- Page 10 uF units used in this circuit. Simply make sure that correct polarity is followed for all electrolytic capacitors. 17. Install C7, a .47 uF electrolytic. 18. Near the volume control, install R19, 4.7K (yellow-violet-red). 19. Install R1, 10K (brown-black-orange). 20. Near S1, install electrolytic C26, 47 uF. 21.
- Page 11 40. JMP13. 41. JMP16. 42. JMP10. 43. JMP9. 44. JMP8. 45. Install C12, 470 uF electrolytic, watch polarity. 46. Install R6, 10K (brown-black-orange). 47. Install R7, 47K (yellow-violet-orange). 48. Install C4, .47 uF, watch polarity. 49. Install C8, .47 uF, watch polarity. 50.
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Page 12: Schematic Diagram
SP1 SCHEMATIC DIAGRAM SP-1 • 12... - Page 13 notched/ banded end facing the rear of the board as illustrated. There is no need to use a socket, but if you do, use care in soldering the socket and inserting the chip. 62. Install U2, 8-pin audio amplifier IC LM386. 63.
- Page 14 2. Set both S1 and S2 to their "out" or off position. Set the volume control to a mid-range point. 3. Next, test the modular phone cord you intend to use with the SP1, even if it is brand new. Do this simply by trying it on another telephone. Then, connect the cord between the SP1's J2 and a working, correctly-wired phone jack.
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Page 15: Initial Testing
should drop out when you speak and return when you are quiet. 8. With S2 (Mute/Hold) pressed IN, you should still hear the dial tone, but the microphone should not respond to even a loud yell. 9. Turn S1 OFF; this is the equivalent of putting a phone handset back "on the hook."... -
Page 16: Optimizing Your Set-Up
SP1 Speakerphone. RINGER CIRCUITS: The SP1 does not include a ringer circuit for the simple reason that the average home, shop or office already has plenty of ringer noises whenever there are phone calls. If you are a telephone electronics enthusiast and really want a built-in ringer circuit, it is up to you to understand and comply with telephone company ringer circuit equivalency requirements. -
Page 17: Understanding Speakerphones
Because we take telephones so much for granted, it is easy to not care or appreciate the many functions and features of the SP1 and the MC65118 IC. That's OK: if it's working fine, then just enjoy it and don't worry about how it works. -
Page 18: Optional Battery Operation
IMPORTANT: Use a battery for this purpose, not a DC power supply. It is important to remember that the telephone line loop voltage is a minus 48 volts DC with respect to earth ground. Introducing a common AC mains ground at the phone line input may damage SP1 components. SP-1 • 18... - Page 19 As mentioned, S1: A performs the same function as a conventional telephone "hook" switch. As soon as S1 is pressed in, the central office equipment is able to sense that the SP1 is connected to the line or "loop."...
- Page 20 DESCRIPTION Filter output Filter input Chip disable (not used in SP1design). Vcc (DC supply voltage) Hybrid amplifier output #2 Hybrid amplifier output #1 Input to hybrid amplifier #1 TX attenuator output TX attenuator input Microphone amplifier output Microphone amplifier input Mute input (mike amplifier muted by + DC at pin 12 ) Volume control input Response time to switch between transmit and...
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Page 21: Intercom Operation
Texas Instruments Learning Center. ENCLOSURE & SPEAKER CONSIDERATIONS: The SP1 may be finished off nicely with its custom Ramsey case and knob kit, running standard speaker wire to an extension speaker in any location convenient for you. Or, the PC board may be mounted within a speaker enclosure of your choice. - Page 22 PARTS LAYOUT DIAGRAM SP1 SPEAKERPHONE KIT: SP-1 • 22...
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Page 23: Warranty
10K ohm resistors and received five extra 1K resistors, you can pretty much be assured that the '1K ohm' resistors are actually the 'missing' 10 K parts. Ramsey Electronics project kits are packed with pride in the USA. If you believe we packed an incorrect part or omitted a part clearly indicated in your assembly... - Page 24 SP1 SPEAKERPHONE-INTERCOM KIT Quick Reference Page Guide Introduction to the SP1....4 Parts list for the SP1 ...... 5 Parts layout diagram ...... 6 Assembly instructions..... 7 Schematic diagram....... 12 Initial testing........15 Understanding Speakerphones..17 Intercom operation ....... 21 Warranty ........
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