Group Inputs/Outputs. Connection points exist for 13 group inputs/outputs. From these, a maximum
of 8 may be selected for use (8 ports max available). The facing page chart defines which type(s)
of group inputs/outputs (formats) can be accommodated by each port. Listed below the chart are
the possible data rates for each format. As indicated by note 3, group data rates of 1024 and
1152 kb/s require the use of two ports.
Each received SG is demultiplexed (recombined) into its composite parts by a demux. Applicable
group data is then switched to its designated port for output to the group. Thus, inputs and outputs
for a given group use the same numbered port.
The conditioned diphase group modem input/output also provides for a combined digital orderwire
to be received/transmitted along with the group data. This combined digital orderwire is available
when group data rate is 256 kb/s and above and includes 16 kb/s of DVOW.
The VI model has a TD-976 mode. If this mode of operation is selected, a 4915.2 kb/s balanced
NRZ input is accepted at input port 8 and becomes the output SG. In the return direction, a 4915.2
kb/s SG input is received and routed through demux 1 to port 8. No multiplexing or demultiplexing
is performed nor are orderwires available in the TD-976 mode.
Dedicated User. A 16 kb/s or 32 kb/s dedicated user option is available. If this option is used,
data from the dedicated user is included in the multiplexed output SG. One of the four received
SG'S will contain data for the dedicated user. That particular demux will be selected to complete
routing of data to the dedicated user.
Orderwires. A 16 kb/s DVOW capability is available and has two operating modes (non-secure
and secure). Mode selection is controlled by the operator. Earth side interfaces are with a H-250
handset, a KY-57/58 Vinson, and a communications nodal control element (CNCE). The CNCE inter-
face is through the combined digital orderwire that is part of the conditioned diphase group modem
input/output. The Vinson and CNCE are secure orderwires.
The term "local" means your TD-1337(V)/G and the term "remote" means TD-1337(V)/G's that are
on the other side of the satellite. Local and remote TD-1337(V)/G's must be in the same orderwire
modes to conduct a conversation. Following is a list of points between which 16 kb/s DVOW con-
versations can be conducted.
H-250 handset to H-250 handsets at remote TD-1337(V)/G's
Vinson to local CNCE
Vinson to Vinsons at remote TD-1337(V)/G's
Vinson to CNCE at remote TD-1337(V)/G's
CNCE to Vinsons at remote TD-1337(V)/G's
CNCE to CNCE at remote TD-1337(V)/G's