AMD AMD-3700 Manual

Introduction and Overview

The AMD-3700 Telephonic Stethoscope provides high quality remote auscultation with a number of valuable and unique features.

• Low bandwidth while achieving quality auscultation. The AMD-3700 connects to the system Data Channel via an RS232 interface operating at 19.2 Kb/s.
• Same model can be configured for Transmit operation or Receive operation.
• Plugging in the Chest Piece Assembly automatically puts the unit into Transmit Mode and illuminates the TX Mode light.
• In Transmit Mode, the same auscultation sounds that are sent to the remote AMD-3700 unit are also presented at the Headset jack for local monitoring.
• Leaving the Chest Piece input jack empty automatically puts the unit into Receive Mode and illuminates the RX light.
• Volume control for adjusting the sound level delivered to the Headset jack. The Volume control works in Receive Mode for sounds received from a remote AMD3700 unit or in Transmit Mode for monitoring sounds generated from the Chest Piece Assembly plugged into that local unit.
• B/D Switch for an enhanced Bell/Diaphragm selection. The Bell (B) position cuts off the high end at 250 Hz and boosts the low frequencies below 100 Hz for enhanced heart auscultation. The Diaphragm (D) position slightly reduces the very low frequency sounds and extends the high frequencies to 1,400 Hz. The B/D Switch works in Receive Mode for sounds received from a remote AMD3700 unit or in Transmit Mode for monitoring sounds generated from the Chest Piece Assembly plugged into that local unit.
  The AMD-3700 Telephonic Stethoscope is for prescription use by medical care professionals.

Installation

Installing the AMD-3700 Telephonic Stethoscope is as easy as applying power and connecting the unit to a functional Data Channel.

1. Power
   Power is provided to the AMD-3700 unit from a small, wall mount Power Supply. Plug the Power Supply into a 115 vac wall outlet and insert the plug at the end of the power cable into the jack at the left rear of the AMD-3700 unit.
   If there is no Chest Piece Assembly plugged into the unit, the RX Mode light will be lit and the TX Mode light will be OFF. If a Chest Piece Assembly is plugged into the unit, then the TX Mode light will be lit and the RX Mode light will be OFF.
2. Data Communications Channel
   The AMD-3700 Telephonic Stethoscope data interface is in asynchronous format with:
   • RS232 electrical voltage levels
   • 19.2 Kb/s data rate.
   • 8-bits per character.
   • No Parity.
   • One Stop bit.
     The Data Communication Channel interface must be set up to match this specification.
     The AMD-3700 Telephonic Stethoscope functions as a DTE in terms of data communications. If the Data Channel linking the transmitting AMD-3700 unit to the receiving AMD-3700 unit is to be a modem, multiplexer or other similar DCE, then (probably) a straight-through cable should be used to connect the AMD-3700 units to the Data Channel interface. The AMD-3700 unit has a male DB-9 connector at the rear of the unit. Typically, DCE equipment will have a female DB-9 connector for its data communications interface. In that case, a female DB-9 to male DB-9 straight through cable should be used. Sometimes DCE equipment will have a DB-25 connector for its interface. In that case a DB-9 to DB-25 adapter may be used, or a cable with a female DB-9 connector at one end and a male DB-25 connector at the other end.
     If a PC is used for the Data Channel interface, then it is important to know that the Serial Port (COM Port) of a PC is a DTE interface. In that case (or any situation where the Data Channel equipment interface is DTE), a cross-over (or null modem) cable is needed with a female DB-9 at both ends of the cable.
     Before connecting the AMD-3700 units to the Data Channel (or if data communications problems arise), it is a good idea to test the AMD-3700 units back-to-back to verify that they are working properly by themselves. Apply power to both AMD-3700 units and interconnect them with a male DB-9 to male DB-9 cross-over cable as shown below.
     If sounds from the Chest Piece are heard at the headset, then the AMD-3700 units are working properly and if problems arise in connecting the unit to the Data Channel, it is appropriate to the concentrate on getting the signal through the Data Communications Channel.
     
3. Mode Selection
   If there is no Chest Piece Assembly plugged into the Chest Piece jack of the unit, then the unit will be in Receive Mode and the RX Mode light will be illuminated. The TX Mode light will be OFF.
   If a Chest Piece Assembly is plugged into the Chest Piece jack of the unit, then the unit will be in Transmit Mode and the TX Mode light will be illuminated. The RX Mode light will be OFF.

Operation

For a normal remote auscultation exam, the AMD-3700 unit located with the patient is in Transmit Mode and the AMD-3700 unit with the clinician is in the Receive Mode.

1. TX Mode
   To operate as an auscultation transmitting unit the AMD-3700 must have a Chest Piece Assembly plugged into the Chest Piece jack. That will put the unit into Transmit Mode and illuminate the TX Mode light located just over the Chest Piece jack. Sounds from the Chest Piece will be converted to digital signals and sent out over the RS232 data interface.
   In addition to transmitting the digital signals, the auscultation sounds from the Chest Piece are looped back and presented at the local Headset jack. Thus, with an optional Headset, the local user can listen to the same auscultation sounds that the listener at the remote AMD-3700 (in Receive Mode) would hear.
   Volume to the Headset can be increased by turning the Volume control clockwise. Increasing the volume too high can cause distortion in the Headset and will also increase the background noise. Start with the lowest volume necessary to hear the sounds, then turn up the volume as needed to focus in on specific sounds.
   The B/D Switch can be used in an auscultation exam similarly to a traditional stethoscope. The Bell (B) position cuts off the high end at 250 Hz and boosts the low frequencies below 100 Hz for enhanced heart auscultation. The Diaphragm (D) position slightly reduces the very low frequency sounds and extends the high frequencies to 1,400 Hz.
   Adjusting the Volume or changing the B/D Switch only affects what the local listener hears and does not affect what the remote AMD-3700 listener would hear. The remote AMD-3700 listener has independent Volume and B/D Switch controls.
2. RX Mode
   Without a Chest Piece Assembly plugged into the Chest Piece jack of the TR-1, the unit is automatically in the Receive Mode. With the Data Communications Channel established and a Headset plugged into the Headset jack of the unit, the clinician is set up to hear the stethoscope sounds from the remote AMD-3700 (in Transmit Mode).
   Volume to the Headset can be increased by turning the Volume control clockwise. Increasing the volume too high can cause distortion in the Headset and will also increase the background noise. Start with the lowest volume necessary to hear the sounds, then turn up the volume as needed to focus in on specific sounds.
   The B/D Switch can be used in an auscultation exam similarly to a traditional stethoscope. The Bell (B) position cuts off the high end at 250 Hz and boosts the low frequency sounds below 100 Hz for enhanced heart auscultation. The Diaphragm (D) position slightly reduces the very low frequencies and extends the high frequencies to 1,400 Hz.

Maintenance and Calibration

There is no scheduled maintenance required for the AMD-3700 Telephonic Stethoscope.
There is no calibration required for the AMD-3700 Telephonic Stethoscope.
If problems should arise with the AMD-3700 Telephonic Stethoscope, the table in the following section may be used to trouble shoot the problem. Any failed units should be returned for repair.
The AMD-3700 Telephonic Stethoscope may be cleaned with a damp cloth.

Trouble Shooting

Following is a chart to assist in trouble shooting problems which may arise during installation or operation.