Specifications

Appendix A – TAP Interface Specifications - 11
PAGING OPERATION
Paging transactions are transmitted in blocks of characters, where one transaction is sent per block. Each
block sent by the Host Device is acknowledged by the paging system. The Host Device must wait for this
acknowledgement before sending the next block. The SPS-5 Paging System provides acknowledgement in
the form of an <ACK> character.
The SPS-5 Paging System supports TAP message blocks up to 253 characters in length, with a 235 to 244
character message, from 1 to 10 characters for ID (pager number), plus 5 control characters, and a 3 character
checksum. (Message field length is restricted as follows: when a 1 character ID is used, a 244 character
message can be accommo dated, and so on, for a total of 253 characters, such that when a 4 character ID is
used, a 241 character message can be accommodated. The maximum ID field length of 10 causes a maximum
message field length of 235 characters). A block always carries two fields with their associated carriage
returns. The message field may be empty, but it’s carriage return must be included in the data block. The
TAP message block format is as follows:
<STX>ID<CR>Message<CR><ETX>Checksum<CR>
The ID field is a one to ten character pager number. Leading zeroes are not required. The Message field
accommodates up to 235 alphanumeric characters. The Checksum field provides a checksum for the
previous portion of the TAP message block. See Appendix D – TAP Checksum Calculation, for sample code
to create the checksum field.
The Message field can be formatted as follows:
• For alphanumeric paging messages, all 7-bit ASCII “non-control” characters are valid except ^, ~, and _
(underscore)
• For numeric paging messages, valid characters are the numbers 0 through 9, - (hyphen), and space
• Control characters can be embedded into paging messages so that high end alpha pagers and paging
data receivers can respond with formatted screen displays and with formatted serial output, as required.
Control characters (typically <CR> and <LF>) can be embedded in messages by using the
Transparency Option. The Transparency Option replaces a non-printable control character with the
SUB (Hex 1A) character immediately followed by the control code offset by 40 Hex. See Appendix G -
Embedded Control Characters for details on how to embed control characters in paging messages.
The WaveWare TAP interface supports ID field lengths from 1 to 10 digits. The ID field can be formatted
using two different methods, as follows:
• Method 1 - ID field lengths from 1 to 4 digits will cause a pager database lookup. ID fields of this format
must contain numeric digits only. The numeric ID value will be compared to the ID values stored in the
SPS-5 Paging System’s onboard pager database.
• Method 2 - ID field lengths from 5 to 10 digits will cause Extended ID processing. Extended ID
processing assumes that the last 3 digits of the ID field define paging message encoding attributes,
while the preceding digits define the pager capcode. Extended ID processing allows you to avoid the
process of configuring a pager database in the SPS-5 Paging System. See Appendix E – Extended ID
Processing for details on how to format the ID field.
When the Host Device delivers a TAP Message Block to the SPS-5 Paging System, if the message block is
properly formatted, and a 1 to 4 digit ID field matches the pager database, the paging system will respond
with an initial response code as follows:
211 Page(s) Sent Successfully<CR>