[rescue] What use is this CAB-530MT Cisco cable?

[Patrick Giagnocavo]

I have a new in shrinkwrap CAB-530MT which is Cisco HD60 to RS-530  
(looks very much like a standard DB-25 pin serial except a pin or two  
is missing).  Description says it is a "Male DTE RS-530 cable".

What exactly would this be used for?

Google says that it can be used to transport up to 10Mbps of  
bandwidth, or less depending on cable length and quality of signal.   
Apparently RS530 is not a protocol, just a physical interface standard.

Patrick Giagnocavo
patrick at zill.net