Ship to Ground Communications

The next higher organizational level for the overall communications system involves contact and information exchange between the starship and planetside personnel and remote equipment. Communications external to the spacecraft are routed from the main computers to the radio frequency (RF) and subspace radio system nodes.

While the term
"radio" is something of an anachronism, since Starfleet communications more often than not involve visual information, it nevertheless
continues to describe the basic function of the system. Normal radio frequencies are set aside as backups to the primary subspace bands,
though RF is in continued use by numerous cultures maintaining relations
 with the Federation, and Starfleet vessels must sometimes rely on this
older system when subspace bands prove unusable due to stellar or
geological phenomena, or when hardware difficulties arise with either
the host or remote sides. Such space-normal radio communications are, of
 course, restricted by the speed of light, resulting in severe time and
distance limitations.

#### INSTALLED HARDWARE

The RF section
consists of a network of fifteen triple redundant transceiver assemblies
 cross-connected by ODN and copper-yttrium 2153 hardlines and linked to
the main computer comm processors. All are partially imbedded within the
 structural hull material at degree and distance intervals about the
starship for maximum antenna coverage and manageable antenna timesharing
 loads.

Each transceiver
assembly is a hexagonal solid measuring three meters across the faces
and one-half meter in thickness. Each consists of separate voice and
data subprocessors, eight six-stage variable amplifiers, realtime signal
 analysis shunts, and input/output signal conditioners at the hull
antenna level. RF section power is obtained from Type III taps from the
electro plasma system.

The basic
limitations of the RF section stem from the c velocity limit, and a
normal useful range at moderate power on the order of 5.2 Astronomical
Units (A.U.). RF frequencies directed through the steerable central
component of the main deflector can extend the useful range to some 1000
 A.U., though no practical applications of this power have yet been
demonstrated.

The subspace
transceiver specifications, in proportion, are roughly akin to the warp
propulsion system being compared to its less powerful impulse cousin.
Approximately one hundred times more energy is required to drive voice
and data signals across the threshold into the faster subspace
frequencies, and even when applied to relatively short distances, the
transmission reliability climbs dramatically.

As with the RF section, small transceivers such as the standard subspace transceiver assembly
 (STA) in the personnel communicators need not emit great amounts of
power if the large transmitters and receivers remain on the starship. A
series of twenty medium-power subspace transceivers are imbedded within
the starship hull at various locations to provide communications
coverage similar to that of the RF units. Each triple redundant device
is contained within a trapezoidal solid measuring 1.5 x 2 meters by 1
meter in thickness. The system is powered by Type II electro plasma
system (EPS) taps with a total maximum power load across the twenty
nodes of 1.43 x 102 MW.

Each transceiver
consists of voice and data processors, EPS power modulation
conditioners, subspace field coil subassemblies and directional focusing
 arrays, and related control hardware. Signal handoff from the optical
data network is done with a combination of realtime and sequence
anticipation Al routines for maximum intelligibility, given the FTL
nature of the outgoing and incoming subspace signals.

#### APPLICATIONS

Communications
between the starship and a destination typically 38,000 km to 60,000 km
away from the antennae are handled by the above-mentioned radio systems.
 Situations encountered cover a broad range, but most notably include
discussions with planetside governments, communication and control of
Away Team operations, local and regional crisis management, data
collection from remote and active occupied research stations,
shuttlecraft departure and approach terminal guidance, and Starfleet
search and rescue.

The subspace
transceiver network is the active system linked to the transporter for
personnel locator and coordinate lock-on functions. A minimum of three
transceivers covering a given portion of the spacecraft sky coverage
must be available for reliable transporter lock. The maximum reliable
distance for routine transport is 40,000 km, owing to the median matter
stream blooming tolerance of 0.005 arc-seconds, though subspace
communications by the medium-power network can extend to some 60,000 km.

Normal contact
with the starship, if externally initiated, is divided into two basic
types: Starfleet personnel, especially those persons directly assigned
to the ship, and non-Starfleet agents. Away Team members will call
directly to the Bridge or other active departments during the course of
their work.

Normal contact
from outside agents will be held by Security for presentation to the
captain or other senior officers. Emergency transmissions will usually
be passed without computer delay for appropriate action.

Standard
encryption/decryption, plus enhanced security encryption protocols, are
handled by FTL processors within the main computers. Starfleet
encryption algorithms are rotated and updated on a random schedule.

Multiple private
key portions are retained with the starship computers, and the public
portions are transmitted to Starfleet-issue hardware, such as handheld
instrumentation, communicators, personal access display devices, and
other pieces of expendable gear vulnerable to possible capture by Threat
 forces. Calling for a secure channel on either the spacecraft or remote
 side will be detected by the main computer, which will place higher
encryption schemes in standby mode to await confirmation by command
personnel.

With certain
non-Starfleet subspace transmission protocols, particularly for data
burst receiving, protocol matching delays may be forced by the computer
until matrix translation values are calculated and applied in realtime.
True Starfleet burst modes, as designed into the standard and medical
tricorders, allow rapid emergency transmissions of stored information
via the subspace system. Single antenna coverage is acceptable, though
the physical layout of the antenna groups assures at least two arrays
will be visible if the spacecraft is in line-of-sight of a transmitter.