Motorola V186 - Cell Phone - GSM System Planner Manual page 99

Communications
from the technical constraints and complexities of network operations thus allowing the
intended application to be the item of focus.
MDLC uses a semi-synchronous data format on two-way radio and an asynchronous
format on wirelines. It is not correct to refer to message size in byte notation because of
the 16-bit architecture; the data may not be sent in asynchronous format—no start and
stop bits—but it is not true synchronous either because there is no single network-
provided clock signal. Instead, each CPU has a clock that is entirely adequate to provide
the synchronize signal for data transfer. It is therefore better to refer to MDLC in terms of
data words where each word may be variable in length, consist of both header and body
components, and contain up to 80 16-bit variables within the body. A physical message
may consist of a single word or may consist of a concatenated series of words (packets),
each word addressed to one or more destination sites with some or all words requiring
subsequent store-&-forward operation by the recipient site(s). The concatenated data
words may be any combination of the supported functions, i.e. data upload to the
SCADA Manager, error logger data to the STS/ToolBox, etc.
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