Telex user manual Wirsri?rcddsrrninssthe~opwrtingdist.nCc, Ths CM300URM300L with 25 ohm

Wirsri?rcddsrrninssthe~opwrtingdist.nCc

(where theDC voltage drop is the limiting factor). Ths following eqlutioas apply for a wndnctor sizeof #22 AWG.a minimwnuser station voltage of 18.0 volts, d a minimum power supply voltage as stated below.

For Modds PSlO, PSM, PS31, P M , PS60, usa Vmin =

28.4VDC:

-D	(feet) P 322,181 1Ibt-( . .	1.
D h -	(mtgs)= 99,133 1Im (milliPmperes)

For Models PS8, PSl5 (Vmin = 24.0 MC):

. .

(feet) = 185,874 1Im (rmllumpcrcs1

D h c e - (map) = 56,654 1I&# (milli.mpsrss)

Exnmpk:	Ths CM300URM300L with 25 ohm
~ u s a	r u p t o 6 0. .	. With a PS8 supply

the maximum c p a h g ~ f o thisr anti011 is

185,874160 ''	= 3098 fkt (944 mstas). Asd
with a PS3l-y	the muimomopsnting dishlLce
	= 5370 feet (1652 mtgs).

md a usa station with 25 ohm phollg (37mA) is 185,874EV = 5024 feet (1531-).

Anotha bmsfit of not "earth" grounding the circuit return is tht it prevents the h t m h t i o n of noise through 'earth" curw(sfrom other equipmeat. If the RTS Systmes circuit

gmund~tsthsc~l~nts,itisWrdythattheywillbc

hevd is interfering noise on thed 4 o n line.

Wirin~lC&&g(See Cable Wiring D	i in Section 7,
Application Momati011)

Two c h m d 'TW' applications, or single c l l m l d , thma wiro a p p l i ~ & ~IMY~ USE ather e~ ~ C ~ O ~ I I O cableD C (for canrmimcs) or hmhvkhl-paircable (Isss expensive tbrmmicqhomcnble). S I a n d a d w i r c r i z c f o r t h e ~

is#2zgougswiroforinkm=&h. F o r y t

iumWi01u arch chtlmd should have m i~~J~wdually shieldedtwistalpirof.tlasr#2zgurgewirc;wrchis

8723 for 2 ~ b m n dUUCI~ , mn for 3 cbmnels. POX plenum md I or 2CV' C wiring, use Bddea 88723 md 88777. Thsplaaum able hna a slighUy smaller d*metcr, isTefbninsul.tsd, d.boutthree. timgthepriceof 8723

18777.

System circuit g r d should not b k t l y c o n d to		W i r e u s i n g c a b l e W i ~ , S e c t i o n 7 , t o r e d u c e
		intdemim UUCI help maintain a low crossc.1L f i p
'euth'or'chssis'zmund(dirseclvmesnsacamectionmbstmea*.
ohmmtawwld&).	~ g C T 8 1 . l i o n i s b ~ t o
its own chassis via a 0.1 microfaadcapacitor, stabli6biug			Liac levd is bchmwa 1OdBu md OdBu
a r P d i o f i . q l l c I I c y ( R F ) ~ t o r a d u e s n d i o ~The audio a&
i n ~ c e f m m n d i o t n n s m i ~ .		(bchvecn 0.24	.ad 0.77 volts rms).	Thwe levels are low
		~ t o ~ t ~ i n t o & e q u i p m m t ( s u e b a s
To pre-vent a buildup	of voltage acm(g tbe system ca-	TV amsns) yet high amugh to minimirs extend
p l c i ~ , t h c p o w s r s u p p I y h s a b l s s d s r ~ t o c h . s s i s inmfemcetotheTWSpttm.
ground (22 kilohms). If the system hs no RTS Systems		The 200 ohm Liac i m p d a w is high enough to uUow
pow- supply, add a bleeder mistor at a cmotnl point in
the system.		mnnmmication om liae lengths of 1.6 kilometers (one
		mile) d low mwgh to permit m d#lrule speech
The benefit of not 'earth' gnnmdiug the RTS System		bmdwidth with 3.2 kilomttefs of d		a t e d cable. In
		most systems the 200 ohm impcdpace gives a high fidelity
circuit nzum is that continued operation is possible during
nn accidmtrl system ground fault. This awidmtal		bmndwidth with low lwsar.
grounding uo happm whea a wire is pinched or a cable		When using equipmeat in nia or conditions of excessive
scraped.erossasbprpedge. Oncrceidentalgrwndcmb
		moisturr, always protect the equipment with plastic covers
t o l d by the system until the fault can be cleared md
(with luck) b c f m a sccolld ground fnult can cause noise or		md make sure uU cable c~ll~ectcnsme lifted out of mud,

overload or bring the system down.	mow or moisture md pmtected with plastic. Wpter mud
	d s n o w i n ~ ~ ~ ~ c p n c a ~ s ~ n o i s e .

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