User Manual

14
Canoga Perkins
Figure 1-3. Model 2202 Modem Shelf
1.4 Modem Operation
1.4.1 General
The 2240 Modem can use an external clock, provide the master clock, or one end
can be slaved to the other for either of these cases. The electrical connection
between the data equipment and the 2240 Modem differs from model to model
depending on which interface is employed (modem is usually DCE). The electronic
conversion from voltage level to optical signal level is similar in all applications. For
a description of the available interfaces, refer to Section 4. Figure 1-4 provides a
functional block diagram of the 2240 Modem.