NEC 616 manual Co/Pbx

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130Other Consideratiaons

130.1Electrical Noise Generators

Certain equipment, such as welding machines,

thyrister-driven power supplies, large electrical motors, etc. generate electrical noise. As a stored program machine the

Electra-616 System is vulnerable to this noise. When this type of machine is present at an instahation, the following precautionary steps are urged:

1.	Locate	KSU,	telephone	sets,	and cabling	away from
	these machines.
2.	If cables	must	pass near	these	machines,	use shielded
	cabIe with the shield grounded.

140 Specifications

140.1System Capacity

	The Electra-616 system capacity is as follows:
CO/PBX		Lines	6max.
Intercom		Paths	2 max.
Internal		and External Paging Path	1 max.
Station		Sets	16 max.
BLF	Consoles		2 max.
Door	Phones		2 max.

140.2Cabling Requirements

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3. Ensure all machines		of	this	type are well-grounded to a
separate ground	to	minimize		noise interference.
130.2 Pre-installation	Site		Survey

Since a pre-installation survey is generally required

to plan for application and installation, a check of the matters covered so far in this section at this time will pre- vent later problems.

130.3 Additional Equipment

In addition to electronic station equipment and the KSU and their contents, other equipment is required. This includes cables, modular connecting jacks, quick- connect blocks (or smimlar apparatus), etc. This additional equipment must be locally supplied.

1.Cabling required for Key Telephone Sets, BLF Con- soles, Door Phones is as follows:

1)Required Cable

-Key Telephone Set: Twisted 2-pair cable

-	BLF	Console:	Twisted 1-pair cable
-	Door	Phone:	Twisted 1-pair cable

2)Maximum Loop Resistance and Cable Length at 24AWG

-Key Telephone Set: 40 ohms, 700 ft. (21Om)

- BLF	Console:	40 ohms,	700	ft.	(21Om)
- Door	Phone:	40 ohms,	700	ft.	(210m)

3)Maximum Cable Length at 22AWG

*Key Telephone Set: 1,150 ft. (35Om)

- BLF	Console:	1,150	ft.	(35Om)
- Door	Phone:	1,150	ft.	(35Om)

2.BLF Consoles require a local power supply (provided with each unit), which plugs into a 117V AC outlet. The cable provided with these units is 6 feet in length.

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