Digi 90031300 manual General Rack Installation Directions, T1 Modem Bank Unit Spacer

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

14 T1 Modem Bank