MFJ-434B Instruction Manual Voice Keyer
8
Remote message control lines are provided at the back panel via a male 8-pin IDC plug. This
provides individual access to all five memory lines (MSG1-MSG5) plus the stop message line
(Stop). All lines are isolated by a buffer, and are CMOS and TTL level compatible.
A special output line provides 12 Vdc at low current when the voice keyer is not transmitting.
This line goes logic low when the keyer transmits (Xmit), and can sink more than 20 mA.
Another pin provides a control voltage ground (Gnd), for the control system return path.
These lines are clearly labeled on the back panel for your convenience. The Remote Port IDC
connector may be used to add a remote control box or to provide an interface point for PC driven
message activation. Instructions for constructing a simple remote control switch box and an
external PC interface are provided later in the manual.
Initial Setup
Before powering up your voice keyer, double-check all connections to your transceiver,
microphone, etc. Be especially certain the power source is wired properly and delivering 9-15
Vdc with the center pin positive, and that the supply can handle at least 100 mA. If the supply is
larger than 1 ampere, be sure you fuse the positive and negative lines. Pre-set your keyer's
controls as follows:
Mic Int./Ext: Set as needed--Int for built-in mic or Ext for station's PTT mic.
Xmit: Off (out).
Rec/Play: Play (out).
Volume: 10 o'clock position.
Power: Off (out). Remember to power your transceiver before turning on the keyer.
Repeat Delay: Fully counter-clockwise (CW) for minimum delay.
X10/X1: X1 (out).
Recording A Message
1. Press POWER to ON: The green Play LED should illuminate.
2. Press REC/PLAY switch to REC: The red Rec LED should illuminate and the green Play
LED should extinguish.
3. Choose Audio Source: Audio is available for recording from three sources--the internal mic,
external station mic, and line level Audio In jack. Select as follows:
A. Built-In Electret Mic: Set Mic switch to Int and speak normally about one foot away
from the front panel. Don't crowd the mic element, or distortion may result. Note that
installing a plug into the Audio In jack disables the electret mic. Remove any plug
connected to the Audio In jack before attempting to use the internal mic.
B. Station Mic: Set the Mic switch to Ext and speak normally. Most station mics will not
require PTT activation to record. However, mics with switched audio lines will. In this
event, it's okay to press the PTT switch and speak (your radio will key up, but no audio
will be sent out over the air). If PTT keying poses a problem, disconnect the voice keyer
cable from your radio until recording is completed.
To Next Page
Loading...