Comtech EF Data CDM-550T - Manual (Page 97)

CDM-550T Satellite Modem Revision 3
Clocking Modes MN/CDM550T.IOM
essential to provide an external loop between the ST and TX clock pins. If this is not done, the
modem will assume an async mode, which is not compatible. The loop should be placed between
pin 15 and pin 24 on the 25 pin ‘D’ type interface.
IMPORTANT
FIGURE 10-1 AND FIGURE 10-2, SHOWN ON THE FOLLOWING TWO PAGES,
ILLUSTRATE IN BLOCK-DIAGRAM FORM THE VARIOUS TRANSMIT AND
RECEIVE CLOCK MODES.
10–3