SECTION 3 - BASIC OPERATION
BATCHING
As each page request is received by the Model 16 it can be transmitted
immediately or it can be stored and held for a period of time. There are
advantages to both methods but for the Terminal to be able to perform
either operation it needs a means to store and transmit a large number of
pages efficiently. This requirement is met by the Batching capability of
the POCSAG and Motorola Golay Paging Formats.
A Batched paging transmission is constructed to use the least amount of
air-time possible so that paging throughput is maximized. At the same time
it maintains a structure that permits battery saving operation in the
pagers. An individual page transmission requires a Preamble code, which
contains no information but assists in battery saving operation, and the
actual paging data, which alerts the pager and supplies the display mes
sage, etc.. The Batched transmission makes it possible to transmit a
single Preamble which may be followed by data for a number of different
pagers. The savings in air-time becomes evident in a high throughput system
when the Preamble, which is about a second in length, does not need to be
repeated for each successive page.
To make it possible for the Model 16 to be simultaneously accepting pages
and transmitting others, there are a number of Batching spaces available.
In this way the Terminal can be transmitting the information from one Batch
space while accumulating pages into others. In addition, there is a timer
and a Priority marker for each Batch space. The timer is set to the
Programmed Batch interval when the first page is placed into the Batch.
When the timer has expired the information in the Batch will be
transmitted. The Batch can be sent before the timer expires if the Priority
marker is set. Any priority page placed into the Batch sets the Priority
marker.
TRANSMIT
Paging data transmission from the Model 16 occurs independently from the
reception of page requests. The Transmission sequence begins whenever a
Batch is ready to transmit: either its timer is expired or a priority page
has been placed into it.
REQUEST
To ensure that the Model 16 and another paging terminal, both sharing a
single transmitter, do not try to key up simultaneously, the Model 16
issues a Request to Transmit (RTT) signal when it is ready to start a
Transmission sequence. The signal should be connected to the Terminal Busy
input, if available, of the sharing terminal. The signal might also go to
the Channel Busy input. The programmable Request Hold time defines a period
after RTT is asserted before PTT may activate and is in addition to the
Channel Busy time, if any busy inhibits are asserted.
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