Verilink AS56/56Plus (896-502588-001) Product Manual - Manual (Page 125)

AS56 and AS56 Plus User Manual B-1
Appendix
B
Special Serial Port Cabling
External Timing
If “External” timing is required to satisfy a particular application, Serial
Port #1 must be used (Worksheet Item #24) and Serial Port #1 must
supply the master network timing (Worksheet Item #16). See AS56 and
AS56
Plus
Worksheet, on page 3-30.
External timing is used when the attached customer equipment is a DCE
instead of a DTE. The DCE clock is delivered to the Serial Port’s External
Clock input pins and drives the Access System 56 unit’s transmit
function. See Cables for External Timing, on page B-2.