Unit installation

Chapter 1 Introduction Installation and Operation Manual

1-18 Functional Description FCD-E1

FCD-E1

Customer Premises

User's DTE

DCE

Timing

ML Timing

Data

Channel

DTE2

Timing

Data

Network

Data

Channel

Figure 1-6. Data Channel Timing, Flow of Timing Signals in a Typical Application

In the application shown in Figure 1-6, the data equipment located on the

customer’s premises uses the FCD-E1 link to connect to a data network. Since data

networks include accurate timing sources and do not accept data whose timing

deviates significantly from the network timing, it is necessary to ensure that the

equipment located on the customer’s premises uses the data network timing.

For this purpose, the FCD-E1 connected to the data network uses the data channel

as its timing source, and therefore its main link timing is locked to the data

network timing.

The FCD-E1 located on the customer’s premises uses main link timing. As a result, its

system timing is also locked to the data network timing, and the network timing is

transferred to the data equipment located on the customer’s premises.

To optimize jitter performance, the FIFO size of a data channel operating in the

DTE2 mode can be selected manually (±16 bits, ±30 bits, ±52 bits, or ±72 bits).

The manually selected value cannot be less that the automatically selected value,

which are listed in Table 1-2.

System Management Considerations

System Management Method

The FCD-E1 system is designed for unattended operation. The configuration of the

FCD-E1 system, that is, a complete collection of operating parameters, is

determined by a database stored in non-volatile memory located in the

management subsystem. The database is automatically loaded upon FCD-E1

turn-on, thereby enabling the FCD-E1 to automatically return to its last operating

configuration.