9
Switch S3-7: Reset Software Defaults
Switch S3-7 allows the user to reset the software configured factory
defaults. This will only be needed when using the Model 1001MC to
SNMP manage your units. For more information, please refer to the
Model 1001MC Operations Manual.
S3-7
Setting
On
Normal Operation
Off
Reset
Switch S3-8: Transmit Data (TD) Sampling Point
Switch 3-8 controls the Transmit Data (TD) sampling point.
S3-8
Setting
Description
On
Normal
TD sampled on the falling
edge of the 1089 Transmit
Clock (TC)
Off
Invert
TD sampled on the rising
edge of the 1089 Transmit
Clock.
10
4
4..0
0 IIN
NS
ST
TA
AL
LL
LA
AT
TIIO
ON
N
Once the Model 1089 is properly configured, it is ready to connect
to the twisted pair interface, to the serial port, and to the power source.
This section tells you how to make these connections.
4.1 CONNECTING THE TWISTED PAIR INTERFACE
The Model 1089 supports communication between two DTE
devices at distances to 5 miles (8 km) over 24 AWG (.5mm) twisted
pair wire. Two things are essential:
1. These units work in
pairs
. Both units at the end of the twisted
pair DSL span must be set for the same DTE rate.
2. To function properly, the Model 1089 needs one
twisted
pair of metallic wire. This twisted pair must be
unconditioned
, dry, metallic wire, between 19 (.9mm) and 26
AWG (.4mm) (the higher number gauges will limit distance).
Standard dial-up telephone circuits, or leased circuits that run
through signal equalization equipment, or standard, flat modu-
lar telephone type cable, are
not acceptable
.
The RJ-45 connector on the Model 1089’s twisted pair interface is
polarity insensitive and is wired for a two-wire interface. The signal/pin
relationships are shown in Figure 3 below.
NOTE:
Based on the DTE rate chosen, the Model 1089 will
automatically select the optimum line rate depending on dis-
tance and line conditionsfor the distance. The line selection will
be based on the lowest line rate that will support the DTE rate.
Figure 3.
Model 1089 RJ-45 twisted pair line interface.
1 (N/C)
2 (N/C)
3 (N/C)
4 (2-Wire TIP)
5 (2-Wire RING)
6 (N/C)
7 (N/C)
8 (N/C)
1
2
3
4
5
6
7
8
IMPORTANT!:
The Model 1089 has been optimized for per-
formance at high bitrates (DTE rates greater than 512 kbps). To
ensure accurate performance at these bit rates, please use twist-
ed pair line interface cable that is at least 330ft (100m) in length.
