![background image](http://html1.mh-extra.com/html/ramsey-electronics/sp1/sp1_manual_3604730021.webp)
SP-1
•
21
NOTE ON SPEAKER PLACEMENT:
In general, the SP1's speaker audio will sound best if the speaker is of
reasonably good size and quality and is properly enclosed or "baffled." It should
face the same direction as the microphone or away from it, not directly at it.
Remember that it is a basic function of the speakerphone to detect incoming
audio and quickly attenuate the microphone circuit. Therefore, audio feedback
of the familiar "squealing" kind is not a common occurrence. The feedback
resulting from poor speaker positioning is more subtle: greatly reduced speaker
volume, erratic switching action, possibly with a slight ringing sound.
INTERCOM OPERATION:
Two SP1 units may be used as a hands-free half-duplex wired intercom
system. This offers many handy problem-solving applications for home and
business alike. If you have the practical application, we see no reason why
additional units could not be put "on line."
Phone-line speakerphone operation need not be sacrificed in such local
intercom installations. If you successfully built one or more SP1's, you probably
already have some handy switching ideas. We'll leave those to your ingenuity.
To set up two SP1's for hands-free intercom service, just do the following:
1. Solder a jumper from A to B.
2. Follow all Battery Operation directions in preceding section. (D5, R10,
etc.)
3. Interconnect both units with a modular phone extension cord, or any
other 2-wire pair practical for your setup.
4. Interconnection of further units is up to user testing and
experimenting. In general, keep all "tip" and "ring" lines common to
each other.
Finally....your Ramsey SP1 Speakerphone is designed by us from up-to-date
engineering data to be a hands-on experience in today's electronic telephone
technology. We hope you'll enjoy this very practical implementation of a sturdy
and proven IC. For a wealth of further know-how, ask your Radio Shack dealer
about getting "Understanding Telephone Electronics" (RS No. 62-1388)
developed and produced by 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.
Содержание SP1
Страница 6: ...SP 1 6 SP 1 PARTS LAYOUT DIAGRAM...
Страница 12: ...SP 1 12 SP1 SCHEMATIC DIAGRAM...
Страница 22: ...SP 1 22 PARTS LAYOUT DIAGRAM SP1 SPEAKERPHONE KIT...