MFJ MFJ-464 - Message Memory Details; Message Memory Structure and Capacity; Preparing Messages with ASCII Editors

MFJ-464 Instruction Manual CW Keyer/Reader
36
The Memory
Message Memory
You may compose messages on a computer and load them into the MFJ-464's memory. The
unit's memory system is quite flexible and allows up to four messages to be saved. One message
can call another for additional flexibility. Using the memories, you may prepare the text for a
classroom or over-the-air code practice session in advance. Also, a complete set of QSO
exchange can be prepared and loaded into the MFJ-464. The memory is non-volatile, so it is
saved even when the power is turned off and it does not require battery backup to preserve the
recorded messages.
The unit's 1K memory is organized into four blocks of 256-bytes each, except the last block.
This composes of four individual memory blocks arranged in a stack structure, illustrated in the
diagram shown in Figure 9. The total memory available is 992 characters. Each memory block
is nominally 256 characters, except the last block 4 that has a capacity of 224 characters.
However, an individual message may fill more than one memory block. When this happens,
blocks are filled sequentially, moving upward in the diagram. If a message begins in block 2 or
higher memory blocks, 256 is reserved for each of the previous memory blocks.
For example, a message begun in block 2
will, if longer than 256 characters, flow
into block 3 and then into block 4.
However, it cannot flow downward into
block 1. Because each of these lower
memory blocks has 256 reserved, the
message starting in block 2 can be a
maximum of 736 characters.
Message playback will always start at the
beginning of a message no matter which
memory block of the message you have
selected in the message menu.
Preparing Messages
To prepare messages, use an ASCII text editor on your computer. Valid characters for messages
include all those listed in the chart “Morse Code Character Set” on page 43, the space, tab and
carriage return. In addition, there are special characters, shown in the table below. Any invalid
characters in a message will be ignored when the file is downloaded.
Figure 9: MFJ-464 Message Memory Structure.