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The <CR> character (Hex 0D) is used as an
end-of-line marker in TAP. Some paging terminals have
used other "standard" end-of-line markers such as an
<LF> (Hex 0A) or a combination of <LF>
and <CR>. If the paging terminal sends these
characters (<CR>,<LF> ) or character
combinations (<CR><LF>,<LF><CR>
) when the Remote Entry Device is expecting
to receive a , then the Remote Entry Device should
interpret these characters as the end-of-line. NOTE:
This means that <LF> characters immediately
preceding a <CR> or immediately following
a <CR> may be ignored.
Some systems send "ID=" followed by an end-of-line
marker while others send "ID=" alone.
The "ID=" logon string is preceded by other text or
end-of-line markers on some systems.
The "message continued in the next packet" end of packet
indicator ETB (Hex 17) has been implemented as a US
(Hex 1F) character in some systems.
Many paging terminals allow a <CR> character
to be imbedded in the message text portion of a paging
system transaction. In this case the message itself
is spread across multiple fields (fields #2, fields
#3, etc.) of the transaction block.
Although the TAP transaction block may contain 250
characters of information, the entire block need not
be filled if there are fewer characters to be sent to
the pager. Trailing spaces should be eliminated from
messages in order to conserve "over-the-air" transmission
time when the page request is transmitted.
Most pagers allow display formatting characters to
be sent to the pager for properly formatting the display.
It is recommended that these formatting characters be
used (as specified by the pager manufacturer) if display
formatting is desired. Extra spaces, dashes(-), underlines(_),
and periods(.) should not be used in a message for the
purposes of "formatting" the display of a message in
order to conserve "over-the-air" transmission time when
the page request is transmitted.
There is a message size limitation placed on input
in many systems. Some systems may only accept 80 characters,
200 characters, 1000 characters, or another message
size limit specified by the particular system operator.
Some systems do not support multi-block messages.
In some cases the entire message must fit in one block.
Some systems place a limit on the number of messages
which may be sent on a single connection.
Support for non-printable ASCII control characters
was added in Version 1.6 of the TAP specification. Many
older implementations do not support the non-printable
ASCII characters nor do they support control transparency
insertion. Some older systems will allow the entry of
control-characters if they do not cause a protocol conflict.
The interpretation of, and reaction to, non-printable
ASCII control-characters sent to a paging receiver is
specific to the model of the paging receiver in use.
The response code numbers prepended to the Optional
Message sequences were added in Version 1.6 of the TAP
specification. Older implementations do not prepend
response codes to the message sequence.
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