COMSPHERE ±48 Vdc Central Office Power Unit
directly above the bottom carrier should have its power module installed in the right side of its CO power tray. Then, the next carrier directly above should have its power module installed in the left side of its CO power tray, and so on for the remainder of the carriers in the cabinet. For information on removing and installing a power module, see the Power Module Replacement Instructions section in Chapter 3.
With the power modules placed in alternating sequence, the maximum operating ambient temperatures listed in Table
Independent Mode of Operation
In the Independent mode of operation, the left power module (as viewed from the front of the carrier) powers Slots 1 through 8 of the carrier and the right power module powers Slots 9 through 16 of the carrier. The Shared Diagnostic Unit (SDU), contained in Slot 0, is powered by both power modules. If a power module fails, only the service to that side of the carrier is disrupted. The other side of the carrier is unaffected. Do not remove a
failed power module until a replacement is available. To replace a power module, see the Power Module Replacement Instructions section in Chapter 3 of this guide.
When the power modules are configured for Independent mode of operation, up to six carriers can be mounted in a cabinet. The maximum ambient temperature is 50°C.
The ± 48 Vdc input can be provided in one of two powering options:
•Using two separate ± 48 Vdc power sources and two input power cables.
•Using one ± 48 Vdc power source and two input power cables.
For maximum reliability, use the first option. For more information on these powering options, see the Providing Power to a CO Power Unit section.
To change the mode of operation, see the Setting the Option Straps section.
Table
Maximum Ambient Temperatures Permitted
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| Allowable Number of Stacked COMSPHERE 3000 Series | ||
| Maximum |
| Carriers in a Cabinet |
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| Ambient | 3551 and 3611 DSUs | 3551, 3611, and 3616 |
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| Temperature | 3161 DSU/CSUs 1 | ||
| without DBMs, 3511 | DSUs with DBMs and | ||
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| DSUs, 3151 and CSUs 2 | 3811 Modems 2 |
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| 122°F (50°C) | 4 | 2 | See Note 4 |
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| 113°F (45°C) | 5 | 3 | 13, 2 |
| 104°F (40°C) | 6 | 4 | 3 |
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| 95°F (35°C) | 6 | 5 | 4 |
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| 86°F (30°C) | 6 | 5 | 5 |
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| 77°F (25°C) | 6 | 6 | 6 |
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NOTES: |
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1 | These operating ambient temperatures can be increased by 5°C by placing 3161 DSU/CSUs in cooler | |||
| slots (2, 3, 4, 5, 10, 11, 12, 13), or by leaving a slot empty next to each 3161 DSU/CSU. | |||
2 | Use the strictest cooling requirements when there is a mixture of units installed. |
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3 | Requires a power module on each side, otherwise the ambient temperature must be restricted to 35°C. | |||
4 | A single carrier, equipped with two power modules, can operate at 50°C provided the cooler slots (2, 3, 4, | |||
| 5, 10, 11, 12, 13) are used. |
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May 1998 |