a. General. Each TD-1337(V)/G model has different functional capabilities. Therefore, the number and
types of interfaces vary with each model. For discussion purposes, these interfaces are referred to as
either satellite side interfaces or earth side interfaces. The satellite side of the TD-1337(V)/G interfaces
with the terminal radio equipment. The earth side of the TD-1337(V)/G interfaces with the various data
users, The paragraphs listed below illustrate and discuss the specific interfaces applicable to each TD-
b. Satellite Side Interfaces. Satellite side interfaces are to the MD-945 modem or other equivalent
terminal radio equipment. Signals are the multiplexed supergroup (SG) output and SG'S received for
Earth Side Interfaces. Earth side interfaces are subdivided into the following four categories:
. Group inputs/outputs
. Dedicated user
. CESE telemetry (V3 and V4 models only)
These interfaces are to equipments in the satellite earth terminal and to equipments connected to the
(1) Group Inputs/Outputs. Group inputs/outputs consist of:
. TD-660/G unbalanced NRZ interfaces (V1 and V2 models only)
. Balanced NRZ group interfaces
. Group modem conditioned diphase interface
Each TD-1337(V)/G model has a certain maximum number of ports available to handle group inputs/outputs.
In most cases, a given port can accommodate more than one type of interface. The TD-1337(V)/G operating
configuration will determine which ports are active and select which interface is used at each active port.
A port is defined as the entry and exit point on the TD-1337(V)/G for an active group input/output.
(2) Dedicated User (Loop Modern). All models have a second conditioned diphase interface for
a dedicated user. The rate may be either 16 kb/s or 32 kb/s.
(3) Orderwires. All models have a 16 kb/s digital voice orderwire (DVOW) capability. This 16 kb/s
DVOW may be operated in either a non-secure mode or a secure mode. In the non-secure mode, interface
is with a H-250 handset connected to the front panel. In the secure mode, interface is with a KY-57/58
Vinson. The V3 and V4 models also have a 2.4 kb/s DVOW capability that interfaces with an advanced
narrowband digital voice terminal (ANDVT).
(4) CESE Telernetry. On the V3 and V4 models only, interfaces are provided to facilitate CESE