TYPE NL CABLES FOR RAN (REMOTE ASYNC NODES)
ITEM: RTA000038032
QUESTION:
We have a need for type NL cables. ASKQ has recommended Belden type
9932. This cable uses 24 gauge wire that has individual wire insulation
diameter of 0.054 inches. This will work in the DB-25 connector end
of the cables, but is much to large for the RJ45 connector end. RJ45s
generally are limited to 0.035" insulation diameter. Special oversize
RJ45s may handle larger diameters, but they are too large to be plugged
into adjacent ports of the RAN.
Contacting Belden, one rep suggested type 1540A, another 1536A.
These cables have small conductor so they can achieve the low
capacitance specification of 12 pf/ft. with less insulation
Furthermore they use "step" or dual layer insulation further
reduce the need for insulation thickness. However, even with
this approach the insulation is 0.044 in. dia, which is still to
much for RJ45. The outer layer of the step can be removed (with
great difficulty) to arrive at 0.035 in. dia. which will work in
the RJ45 connector.
We do not want to connect DB25s on both ends and use a pigtail
RJ45 to DB25 converter due to the obvious reliability
degradation, cost, and bulk of an additional connector pair.
(Such a setup would not be type NL cabling)
Does IBM really recommend 9932 for NLs? How can it be used with RJ45
connectors that will connect to RANs? If not 9932, does IBM
support the 1540 (stranded) or 1536 (solid) approach? Is there
some tooling which makes removing the outer step insulation a
simple operation? Any other recommendations?
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A: IBM does not recommend a specific vendor or cable for this connection.
IBM does provide general guidelines in the System Overview (GC23-2406)
for cabling options. The general guideline for the cable NL is as
follows:
Cable length can be up to 61 m (200 ft). Use overall foil/braid
shielded multiconductor cable with a capacitance rating of 41 pF/m
(12.5 pF/ft) or less. Conductors should be 28 AWG (stranded wire).
For lengths less than 61 m (200 ft), higher capacitance cable can
be used as long as the total capacitance does not exceed 2500 pF.
NOTE: 24 AWG stranded wire will work just as well.
Since cable 9932 will not fit in the RJ-45 connector, you would
have to use a pig-tail. So, to achieve a standard NL cable you
will need to use another cable type.
Based on the information which you have provided on cables 1540A
and 1536A, these cables do meet IBMs general specifications on
capacitance. And, apparently, these cables will fit in the RJ-45
connector for the RAN. The "stranded" wire has IBM's official
statement of support. However, the "solid" wire may work. I have
information on a connector that works with 24 AWG solid wire
from a company called Stewart Connector in Glen park, PA. The part
number for this connector is 940-SP-3088-OB.
I have no information on any tooling which will make the removal of
the dual layer insulation for the 1540A and 1536A cables easier.
My only recommendation on this subject is that Beldon, or a cable
vendor, may have some suggestions based on their experience with
their product.
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The response appears to say that IBM does not support type NL cables.
Passing off to the vendors of cables and/or connectors doesn't
constitute adequate support in my opinion.
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A: After further research, I was only able to find a brochure from
Cooper Industries/Belden Division about constructing RJ-45 cables.
The brochure indicates that a special tool XCELITE model number
103-S is used "To facilitate ease of installation, the outer layer
of insulation is easily stripped-away to reveal the inner Telco
color-coded insulation. The cable can then be connected to a RJ-45
plug ...". This is referring to cable type 1540A and 1536A.
Cooper Industries
Belden Division
P. O. Box 1980
Richmond, IN 47375
317/983-5200
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This item was created from library item Q651300 CPBJF
Additional search words:
ASYNC CABLES CPBJF DEVICE EXECUTE HARDWARE IX LINE MAY94 NEW NL
NODES OZNEW OZNOTPID RAN REMOTE RISCADEV RISCSYSTEM RJE TYPE
WWQA: ITEM: RTA000038032 ITEM: RTA000038032
Dated: 06/1996 Category: RISCADEV
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