(5) Line-of-sight radio circuits.
operating space, as indicated on the diagram. Figure
(6) Earth satellite radio circuits.
2-7 shows a typical floor plan for a Technical Control
b. The Technical Control Facility functions to pro-
vide technical direction, coordination, technical super-
b. Primary Patch Bay.
vision of transmission media and equipment, quality
(1) Dc and Digital. The dc and digital primary
control, communications restoral and status reporting.
patch bays are those areas within the TCF where dc
These functions are accomplished with the following
and digital user circuits can be patched, monitored and
five basic operations:
tested. Signals may be high or low level and baud rate
(1) Patching (r&oral, test, monitor).
depending on the user terminal equipment.
(2) Coordination (to far-end, to user, to mainte-
(2) Voice Frequency (VF). The vf primary patch
bay is that area within the TCF where voice frequency
(3) Testing (insertion of a known signal with
circuits can be patched, monitored and tested. Signal
measurement for frequency, level, distortion, etc. on
will have varying levels and signalling schemes de-
an out-of-service basis).
pending on the user terminal equipment.
(4) Monitoring (measurement of existing circuit
c. Circuit Conditioning Equipment. Circuit condi-
conditions or traffic, without insertion of a test signal,
tioning equipment, such as amplifiers, pads, hybrids
on an in-service basis).
etc., signalling equipment, digital line interface units
(5) Reporting (circuit and system status to users,
(DLIU), and circuit ancillary equipment is so installed
adjacent TCF's, circuit distant end, operation and
and wired into the TCF so that it will appear between
maintenance activities, etc., as well as all required re-
the primary and equal level patch bays.
d. Equal Level Patch Bay. The equal level patch bay
c. Normally, the TCF is collocated with a tape relay
is that area within the Technical Control Facility
and switching center, and/or a carrier terminal facil-
where voice frequency channels at the standard Test
ity, but it may be located with either a radio station or
Level Point (TLP (OdBr send and receive)) utilizing
telephone facility. The choice of location is usually
standard in band signalling can be patched, monitored
based on a study of all factors involved in site selec-
tion. By choosing to collocate the Technical Control
e. Group Patch Bay. The group patch bay is that
Facility with the tape relay or switching facility elimi-
area where multiplexed groups (usually 12 channels
nates the necessity of providing additional intrasta-
can be patched, monitored, and tested.
tion links. All circuits, regardless of the media used
f. Coaxial Patch Buy. The coaxial patch bay is that
and type of signal, are available at jack appearances at
a associated with the TCF where signals requiring
the TCF. These appearances provide the flexibility re-
distribution via coaxial cable can be patched, moni-
quired by a TCF. There are exceptions to this rule
tored, and tested. Signals which require coaxial cable
where circuits transit the station on a through group
distribution include supergroup, baseband, high speed
Time Division Multiplexed signals, etc.
level. However, there are group access points, which
allows access to the circuits being carried on a through
g. Dc Circuit Bay (Low/Level) and Digital Patch
group for testing purposes. These access points nor-
Buy. The dc circuit and digital patch bays are those
areas within the Technical Control Facility where low
mally located at the multiplex equipment outside the
level analog or digital data circuits can be patched
TCF, can also be used as patching points for restoral or
rerouting of groups in the event of system failure.
monitored and tested
h. Patch Panel Appearances. Patch panel appear
2-16. Technical Control Configuration
ances are furnished and installed for the following
(1) Allow for substitution for those units which
(fig. 2-6 and 2-7)
are out of service because of test and maintenance of
a. General. The block diagram illustrates the inter-
(2) Allow for substitution of equipment strings
relationship among the major equipment of the Tech-
(circuit or wideband segments) as they occur between
nical Control Facility together with the terminal
the primary and equal level patch panel appearances.
equipment. Although the Technical Control Facility of
i. Time Division Multiplexer Equipment (TDM). The
many DCS Stations may not require access to all trans-
time division multiplexer equipment is a technique to
mission modes shown in figure 2-6, the TCF configu-
accept various digital signals (both data and teletype)
ration should be essentially the same, whether the sta-
with different bit rates and combine them into a single
tion is located at a transmission nodal point or termi-
high bit rate stream for transmission. The demulti-
nal point. The block diagram includes all major equip
plexer section reconstructs the signals at the same
ment and patch facilities which are involved in the
nominal rate at which they entered the multiplexer
overall technical control function, however, all items
This equipment can be used in tandem to accommo-
will not necessarily be located with the immediate TCF