MFJ-495 Memory Keyer
Instruction Manual
36
©
2001-2009 MFJ Enterprises, Inc.
The Memory
Message Memory
You may compose messages on a computer and load them into the MFJ-495's memory. The unit's
memory system is quite flexible and allows up to 32 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-495. 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 8K memory is organized with four banks of eight blocks of 256-bytes each, except the last
block. This composes of 32 individual memory blocks arranged in a stack structure, illustrated in the
diagram shown in Figure 9. The memory banks are labeled A through D. The total memory available is
7.875K (8064) characters, where 1K = 1024. Each memory block is nominally ¼K (256) characters,
except the last block 8D that has a capacity of 128 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 1B or higher memory blocks, ¼K is reserved for each of the
previous memory blocks.
For example, a message begun in block 3A
will, if longer than ¼K characters, flow into
block 4A, then block 5A, and so on. However,
it cannot flow downward into block 2A or
block 1A. Because each of these lower
memory blocks has ¼K reserved, the message
starting in block 3A can be a maximum of
7.375K (7552) characters.
The first character displayed on each message
menu indicates the status of that memory block.
If this character is an open square bracket “[”
(the “beginning-of-message” indicator), the
displayed block is the beginning of the
message; otherwise, it is a portion of the
previous memory block. Similarly, if the last
character is a close square bracket “]” (the
“end-of-message” indicator), the displayed
block is the end of the message. 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.
For example, if the display shows
[1A 2A 3A][4A]
, there is one continuous message occupying
blocks 1A, 2A and 3A and another message in block 4A. In this case, selecting 1A, 2A or 3A for
playback will always start the message from block 1A. This message begins in block 1A, flows into
block 2A, and ends in block 3A.
Figure 9. MFJ-495 Message Memory Structure.