User manual

T1 Modem Bank
14
General Rack Installation Directions
• When multiple units will be mounted in the rack, install a T1 Modem Bank unit in
the first chassis slot at the bottom of the rack, then work upward. This prevents
cables from becoming tangled, and it maintains the lowest possible center of gravity
to prevent the rack from falling over.
• Multiple T1 Modem Bank units within the confined space of a rack may cause
higher operating temperatures. The recommended maximum external ambient
operating temperature of a T1 Modem Bank unit is 40° C. Since the T1 Modem
Bank takes in air from the vent on the bottom of the unit and exhausts the air out
the vent on the side, make sure that neither vent is blocked. The T1 Modem Bank is
shipped from the factory with four “feet” installed on the bottom of the unit. If you
remove the feet, you must ensure that each T1 Modem Bank will have at least 1U
(1.75 inches) of clearance beneath it in order to prevent airflow from being
impeded. You may connect a Digi-supplied spacer (See Figure 6) to the rack
between each T1 Modem Bank unit in order to ensure the required clearance. In
general, eight T1 Modem Bank units can be stacked in a six-foot rack; five units
can be stacked in a 4-foot rack.
• The power cord is limited to 6’ 7” (or 2 m) in length. This is sufficient since most
racks provide internal power outlets.
• The T1 Modem Bank is rated at 1.2 Amps when the current is drawn from a 125 V
AC supply. Due to the nature of the internal switching power supply, the power
rating of the AC supply circuit should be derated to 75% of its rated capacity when
calculating how many units can be connected to the AC supply. For example, a 15
Amp circuit should be derated to 11.25 Amps.
• The T1 Modem Bank should be used only with earth grounded outlets. The earth
ground connection of the three prong cord should be maintained even when the unit
is not connected directly to the AC supply line through a power strip.
Figure 6 T1 Modem Bank Unit Spacer