Verilink AS56/56Plus (896-502588-001) Product Manual - Manual (Page 37)

Configuration Parameters
AS56 and AS56 Plus User Manual 3-13
23. Serial Port, clock normal/inverted.
Depress SELECT to choose Norm or Inv. Initially choose Norm. If
frequent errors occur at this serial port, try Inv and check
performance.
Normally, the down-going clock edge is in the middle of each bit.
This is required by networks. Some DTEs, particularly with high-
speed V.35 configurations and/or lengthy cables, place the rising
edge in the middle of each bit. Inv will correct this condition to
satisfy the network.
24. Serial Port clock handling.
Depress SELECT to choose Internal, External, or Int/Ext.
Internal is the normal setting and should always be chosen unless
there is specific reason to do otherwise. At the serial interface,
Access Syst em56 will provide both TX-clock and RX-clock to the
customer DTE.
External should be used with the Serial Port if the attached user
equipment is DCE, rather than DTE. With external timing, the user’s
DCE must be used as the system’s master clock. See Timing Source
(item #16, above). The “external clock” is the “External Timing” pin
on the interface.
The External setting requires special user cabling and a very specific
configuration for the user DCE. Please refer to Appendix “C” for
more information.
Int/Ext is recommended if the attached user DTE cable exceeds ten
feet in length and the customer data rate exceeds 224 kbps.
Serial Port
Clocks:_Internal
DOWN to
display: