Irob Protection - AT&T MERLIN LEGEND Installation & Maintenance Manual

Installation

IROB Protection

Equipment connected to the analog multiline telephone station
jacks (on the 008, 408, and 408 GS/LS/TTR modules) or to the
MU telephone jacks (on the 008 MLX module) that is located in
a different building from but within 1000 cable feet of the CU
requires IROB (in-range out-of-building) protection units. These
IROBS protect the equipment and the CU from lightning strikes
and power surges. Two units are required for each piece of
equipment — one for the CU end of the wire run, the other for the
equipment end.
Note: No 012 basic telephone modules can be used in IROB
applications.
Use the following IROB protectors:
TII Model 343 (PEC 32918) for analog multiline telephones
and equipment (see Figure 54)
AT&T Model 505A (PEC 32919) for MLX telephones and
equipment (see Figure 55)
WARNING:
The IROB protectors must be installed by an AT&T service
technician, or an authorized representative, or a qualified
installer. For installation instructions, read the CIB that
comes with the IROB protector.
Make sure each IROB protector is properly connected and is
grounded to an approved building ground.
Note: The 505A IROB protector contains fused primary and
secondary protection for two pairs of wires. Auxiliary power
cannot be fed through the 505A protector to terminal equipment.
3-102 IROB Protection