Browse Prior Art Database

Expanded Role of Stereo Jack Eliminates Power On/Off Switch

IP.com Disclosure Number: IPCOM000123625D
Original Publication Date: 1999-Feb-01
Included in the Prior Art Database: 2005-Apr-05
Document File: 4 page(s) / 174K

Publishing Venue

IBM

Related People

O'Neil, GE: AUTHOR

Abstract

Disclosed is a technique for utilizing stereo phone jacks to automatically enable or provide power on/off control of portable battery powered devices. The technique minimizes cost by eliminating the need for a separate power on/off switch.

This text was extracted from an ASCII text file.
This is the abbreviated version, containing approximately 50% of the total text.

Expanded Role of Stereo Jack Eliminates Power On/Off Switch

   Disclosed is a technique for utilizing stereo phone jacks
to automatically enable or provide  power on/off control of portable
battery powered devices.  The technique minimizes cost by eliminating
the need for a separate power on/off switch.

   Battery powered portable devices frequently have tethered
peripheral interfaces supporting serial digital data, remote
switching, or analog transducers such as microphones, speakers,
environmental sensors, etc.

   Many such devices are serviced by simple two wire
electrical interfaces employing standardized phone plugs and jacks
due to their high reliability and relatively low cost.  Stereo jacks
are compatible with both monaural and stereo plugs with little
difference in cost over their monaural counterparts.

   Monaural plugs short circuit the ring to the sleeve of
stereo jacks (Figs. 1 & 2) and the ring connection is normally
unused or considered a redundant return path or ground connection.
The battery return (Fig. 1) or the returns of individual circuits
(Fig. 2) can be connected to the ring of stereo jacks serving one or
more monaural peripherals.  Power on/off control occurs automatically
with the plugging and unplugging of the peripherals.

   Stereo jacks provide power on/off control of all circuits
by plugging in any peripheral (Fig. 1), or selectively control power
to only those circuits associated with each respective peripheral
(Fig. 2).  The latter maximizes power savings when only some features
of a product are exploited at any given time.

   EXAMPLE 1 (Power control to all circuits).

   Fig. 1 illustrates how stereo phone jacks (J1 or J2)
provide power on/off control in a portable Low Power Transceiver.

   The transceiver in Fig. 1 consists of a transmitter (1), a
receiver (2) which includes an audio output amplifier (3), and a
battery supply (4) for power.  Two stereo phone jacks (J1 and J2)
are employed in this example.

   J1 serves as information input to the transmitter (1) via
its tip connection.  This could be a keying line for CW, a digital
modulation interface  for on/off keying, or an analog input as in
the case of a wireless microphone.

   J2 serves to output the detected information from the
receiver (2) via the audio output amplifier (3).  This could be
demodulated digital data, control tones, voice, music, etc.

   With no peripherals attached, the negative (V-) side of
the battery (4) is floating (no return to ground).  No power is
consumed by the transceiver and it is therefore powered off.

   The act of plugging a key, data line, or microphone into
the Tx Key jack J1 using a monaural plug provides the negative (V-)
side of the battery (4) a return path to ground via the ring/sleeve
short and the transceiver is powered on.

   Plugging an earphone or speaker into the Audio Out jack
J2 using a monaural plug completes an alternate or redundant return
path to ground for the V- sid...