Verilink DIU 2130 (880-503297-001) Product Manual - Manual (Page 40)

DIU 2130 Configuration
3-16 Verilink
6. A,D&I NET—The CSU is in drop and insert mode and both the
T1 equipment port and a DIU are in use.
DIU Clock These options determine the source for the TRANSMIT clock that is
used by the CSU to send toward the T1 network. In all cases the
RECEIVE clock is derived from the incoming T1 datastream received
from the T1 network.
The DIU Clock submenu is:
(1)THRU (2)INT (3)EXT 422 (4)EXT TTL (5)NET (6)EQ (7)TIU (8)DIU >
1. THRU—Selects passive timing behavior. The CSU uses the
clock provided by the connected local DSX-1 equipment to
drive the network signal. THRU is recommended in many cases
for drop and insert mode and it is the actual mode in which
the CSU functions when it is in CSU mode. Even though some
selection other than THRU may appear as the current value, if
the CSU is in CSU mode it is actually operating with THRU
timing.
2. INT—Selects the oscillator built in to the CSU card as the
timing source. This is often used in mux mode. INT should
only be selected at one end of a point to point T1 and only if
the T1 does not have timing applied to it by the service
provider (phone company).
3. EXT 422—Selects the balanced pair of input leads that are
present in the DIN connector on the CIM behind the CSU. Use
of this option requires that the external clock being provided
must be at 1.544 MHz in a balanced signal which meets RS422
specifications. EXT 422 might be used in any CSU mode.
4. EXT TTL—Selects the unbalanced pair of input leads that are
present in the DIN connector on the CIM behind the CSU. Use
of this option requires that the external clock being provided
must be at 1.544 MHz in a +5V to 0V signal level. EXT TTL
might be used in any CSU mode.
5. NET—The most widely used value for this option. If it is
known that the T1 passes through a DACS or if the far end CSU
is set for INT clock, then always choose NET. NET is commonly
used in mux mode and may occasionally be used in drop and
insert mode for situations where the T1 equipment does not
provide a reliable clock source. When connecting to a
fractional T1 or frame relay T1 and operating in mux mode
always select NET.
6. EQ—Similar to THRU. The clock signal derived from the DSX-1
T1 equipment is used as the transmit clock source for the CSU.
This choice is invalid for mux mode, may be useful in drop
and insert mode.