Table of Contents
Advertisement
SDM-309B Satellite Modem
4.2.1 IBS/M1200P Interface
4.2.1.1 Functional Description
The IBS Interface module (Figure 4-2) consists of two PWB's that are married together.
The two assembly numbers are AS/1010 and AS/1011. Figure 4-3 is a block diagram of
the IBS/M1200P Channel Unit. Figure 4-4 is a fault and alarm tree designed to explain
the fault and alarm reporting matrix that is designed in the IBS/M1200P Channel Unit.
Refer to Section 3.1.6 (Faults) and Section 3.1.2 (LED Indicators) for a detailed
description of the faults and alarms.
The IBS Interface module provides fully compliant baseband processing in accordance
with Intelsat IESS-309 for serial data rates of 64, 128, 256, 384, 512, 768, 1536, 1544,
1920, and 2048 kb/s. IESS-309 framed operation is not supported by this interface.
Control parameters including data rate may be set by the customer in the interface
configuration menu either from the front panel or remotely through the RS-485 or RS-
232 interface (see Section 4.1, M&C of the modem manual).
4.2.1.2 Data Interface
The module provides three field selectable data interfaces: V.35, RS422, and G.703. The
G.703 interface supports only the 1544 and 2048 data rate selections, while all data rates
are supported by both the V.35 and RS422 interfaces.
Data rate selection is done by installing a header on the interface card and connecting to
the proper connector on the IBS subpanel. Figure 4-5 (Jumper Table) describes the
different interface header connections and shows the location of JP1, JP2, and JP3 on the
IBS Terrestrial Interface.
A bidirectional data loop back function, "Baseband Loopback" is provided in this
Section so that the user may determine that his baseband data is reaching the interface.
Refer to Figure 3-2 (Front Panel Menu Tree) for the location of the baseband loopback
function.
4.2.1.3 Transmit Multiplexer
The customer data stream is multiplexed with the Engineering Service Channel (ESC)
and the resultant information (16/15 times the data rate) is interfaced to the
Mod/Demod/Coder Sections of the modem. A phase locked loop generates the output
clock from a user selectable reference. Normally this reference will be the recovered
clock from the data interface, but in certain circumstances it may be desirable to use an
external reference clock. An RS-422 input is provided for this purpose (EXC-A and
EXC-B) and may be selected during configuration. Also available is a 10-5 accuracy
MN/U-SDM309B Rev. #
M&C and Interfaces
4-4–7
Advertisement
Table of Contents
