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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