Access Server Lab Setup

Unanswered Question
Aug 4th, 2008

When connecting an Octal cable's 68 pin connector to the asynchronous serial port on a 2520 series router how are the 8 RJ45 connectors attached to routers on the other end. If you wanted to setup the 2520 router as an access server for reverse telnet for a series of routers into what port would the RJ45 connectors attach from the Octal cable. Would the the RJ45 connectors attach to a routers ethernet port or would it connect to a serial port as I suspect. When connecting to a serial port such as a 2501/2503 router what type of adapator is needed. The only adapters I've seen are RJ45 to DB25. And I'm a little confused because I don't think the serial ports on 2501/2503 routers have 25pin serial ports.

I have this problem too.
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Hi There

I do not think that you can use a Cisco 2520 as an access server. Also I do not think that there is an interface on the back of the 2520 which will allow you to connect a octal cable.

The asynchronous serial ports on a 2520 AFAIK are classed as low speed serial ports and would normally be used to connect to a CSU/DSU.

Normally the Cisco routers that are used with octal cables as access servers are 2509 (proivdes 1 interface for a single octal cable, which provides access to 8 pieces of equipmnet) or 2511 (provides 2 interfaces for two octal cables, and provides access to 16 pieces of equipment).

There are also NM-16A and NM-32A interface cards, which can be added to a Cisco 26xx/36xx router to make it into an access server. But IMHO these router models are too good to be used as access servers in a lab.

If you look at this Ebay posting

you will see a photo of an NM-32A card. Notice that the interface to which the Octal cable connects resembles a SCSI interface, and is not the standard 68 pin Serial interface normally found Cisco equipment.

The RJ45 end of the octal cable is connected to the console port of the router you want to access through the access server and not to the Ethernet or serial port, so usually no adapters are required. However there are some pieces of Cisco equipment (The LightStream 1010 comes to mind) where the console port is indeed a DB25 interface, in which case an Rj45 to DB25 adapter will be required.


Best Regards,



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