Octopus Cable for Canoga-Perkins Fiber Optic Mux

No Hardware Flow Control

Introduction

This custom-made "octopus" cable connects half of one Canoga-Perkins CMX-808 fiber-optic RS-232 multiplexer to a patch panel or 8-port harmonica with 6-wire 6-position RJ11 jacks. The patch panel or harmonica must be USOC-wired and have a male Telco connector, since this cable has a female Telco connector.

The RJ11 jacks will be wired without hardware flow control. To implement hardware flow control either use a different octopus cable (or for just one or two ports make an adapter that combines two non-flow-control RJ11 jacks to produce one hardware-flow-control RJ11 jack).

Two of these octopi are required to connect an entire fiber-optic multiplexer (8 DB25 connectors, 16 channels).

Specifications

Each octopus consists of:

• 4 Male DB25 Connectors
• 1 Female 50-pin Telco Connector

Each leg is two feet (2') long unless otherwise specified. The wiring is as follows. Use of twisted pair wire is optional, but if it is used, it must be used as shown in the table.

If solder-type DB25 connectors are used, the soldered pins must be protected with heat-shrink tubing (or some other insulation).

	DB25 Pin	Female Telco Connector Pin
		Leg #1	Leg #2	Leg #3	Leg #4
twisted pair	3	27	33	39	45
	7	1	7	13	19
twisted pair	7	26	32	38	44
	2	2	8	14	20
twisted pair	6	30	36	42	48
	7	4	10	16	22
twisted pair	7	29	35	41	47
	20	5	11	17	23

Derivation

The octopus wiring is derived from the table below, as follows:

• Columns 2 & 3 show the desired end result: the DB25 to RJ11 wiring. There are two RJ11 jacks per DB25 jack; the first four rows are for one RJ11, the second four are for the other.
• Columns 4, 5... show the standard USOC harmonica wiring (RJ11 to Telco USOC)
• Comparing columns 2 against 4, 5... gives the resulting octopus wiring (DB25 to Telco USOC)

   

      

         

      
      

         
DB25

         Pin
      
      

         
RJ11

         Pin
      
      

         
Telco Connector Pin
      
   
   

         
Leg #1
      
      

         
Leg #2
      
      

         
Leg #3
      
      

         
Leg #4
      
   
   

      

         
twisted

         pair
      
      

         
3
      
      

         
2
      
      

         
27
      
      

         
33
      
      

         
39
      
      

         
45
      
   
   

         
7
      
      

         
3
      
      

         
1
      
      

         
7
      
      

         
13
      
      

         
19
      
   
   

      

         
twisted

         pair
      
      

         
7
      
      

         
4
      
      

         
26
      
      

         
32
      
      

         
38
      
      

         
44
      
   
   

         
2
      
      

         
5
      
      

         
2
      
      

         
8
      
      

         
14
      
      

         
20
      
   
   

      

         
twisted

         pair
      
      

         
6
      
      

         
2
      
      

         
30
      
      

         
36
      
      

         
42
      
      

         
48
      
   
   

         
7
      
      

         
3
      
      

         
4
      
      

         
10
      
      

         
16
      
      

         
22
      
   
   

      

         
twisted

         pair
      
      

         
7
      
      

         
4
      
      

         
29
      
      

         
35
      
      

         
41
      
      

         
47
      
   
   

         
20
      
      

         
5
      
      

         
5
      
      

         
11
      
      

         
17
      
      

         
23