This attribute is only used when the actualLinkMode is dce. It is
used to determine the clock to be used to recover the receive data. A
DTE interface uses TSET(DCE) and RSET(DCE) for timing.
If the value of the attribute is fromDce, the DCE uses the internally
generated transmit clock to supply both TSET(DCE) and
RSET(DCE).
If the value of the attribute is fromDte, the DCE still uses the
internally generated transmit clock to supply TSET(DCE), but the
receive timing is derived from TSET(DTE) on the link.
The fromDte mode is recommended when the DTE is far away from
the DCE interface. Note that TSET(DTE) is CCITT V.24 circuit
113; TSET(DCE) is CCITT V.24 circuit 114; and RSET(DCE) is
CCITT V.24 circuit 115.