DM16E1 / DM4E1 Operation and Installation Manual - 204-4001-19
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The interfaces can be individually configured to be part or not of the alarm equipment logic. It is possible to
configure the use of up to three external alarms in this logic. The external alarms are connected to
DM16E1/DM4E1 by a DB9 connector located at the rear panel. The external alarms can be, for example,
for ambient use (temperature and humidity) or to detect intrusion into the place where the equipment is
installed (intrusion alarm). Both types of alarm (internal or external), when activated, send monitoring
information via the management system.
DM4E1 and DM16E1 have led (light-emitting diodes) indicators on their front panels to inform the
conditions of:
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local alarm.
•
active test at any interface.
•
functioning/presence of power supply units.
•
indication of local or remote telephone off the hook.
•
status of aggregate and tributary interfaces.
1.1. Aggregate Interfaces Available
1.1.1. Aggregate Optics
There are a number of aggregate optics card options, combining the following parameters:
•
Compatible with both DM16E1 and DM4E1.
•
Operating on a pair of fibers or on only one (TX and RX on the same fiber).
•
Laser transmission power.
•
Type of connector used to connect the fiber optics.
See chapter 6 to obtain more details.
1.1.2. Electric Aggregates
•
E3 interface for DM16E1 and DM4E1, operating in accordance with G.703 of 34,368 kbit/s (E3).
1.2. E2 and E3 Multiplexing Principle
DM4E1 and DM16E1 multiplexers are based on G.742 and G.751 recommendations.
The Multiplexing structure is represented in Figure 1:
a) G.742: 4 E1 channels, 2048kbit/s (first order) are multiplexed generating an E2 channel, of
8448kbit/s (second order);
b) G.751: 4 E2 channels are multiplexed generating an E3 channel, of 34.368kbit/s (third order).
It should be observed that it is possible to form E2 channels with first order tributaries containing or not the
G.704 frame structure, provided the rate is 2048kbit/s. Similarly, an E3 channel can be formed by channels
with a frame structure compatible or not with that of G.742, provided the rate is 8448kbit/s.
An interesting thing about PDH multiplexing is the possibility of using different clocks, in terms of phase
and frequency, at each input point. Eventual differences are automatically compensated by the equipment.
However, the clocks must be within the standards established for G.703:
•
2048kHz ± 50 ppm (parts per million);
•
8448kHz ± 30 ppm;
•
34368kHz ± 20 ppm.
The clocks generated internally by DM16E1 and DM4E1 are within the tolerances above.
