!!An Old Friend of UNIX
Old fashioned [terminal servers|http://en.wikipedia.org/wiki/Terminal_server] are still the best way to remotely access the consoles on a rack of UNIX/Linux servers. 

While new models sell for [more than $1000|http://www.newegg.com/Product/Product.aspx?Item=N82E16833995031&cm_re=terminal_server-_-33-995-031-_-Product] USD, [eBay|http://www.ebay.com/] merchants will sell you an old one for less than $200.

!!Cyclades TS1000
While Cyclades got [acquired by Avocent|http://www.thefreelibrary.com/Avocent+to+Acquire+Cyclades%3B+Acquisition+to+Enhance+Serial+Management...-a0141280890] in 2006, their products can sometimes be [found on eBay|http://shop.ebay.com/i.html?_nkw=Cyclades+TS1000&_armrs=1&_from=&_ipg=] for around $100.

The TS1000 with 17 asynchronous [RS-232|http://en.wikipedia.org/wiki/RS-232] (RJ-45F) ports and one 100Mbps Ethernet is pretty nice. It runs a Linux 2.2 kernel, on a PowerPC chip and has loads of functionality (SNMP, SSHv2, HTTPS, Radius etc.) 

Unfortunately, as there is no universal standard for running RS-232 using 8 pin RJ-45 connectors and 8 wire cables (i.e. [CAT-5|http://en.wikipedia.org/wiki/Category_5_cable] [Ethernet|http://en.wikipedia.org/wiki/Ethernet]), you may have some work cut out for you when it comes to connecting your terminal server and your servers. You might be able to buy appropriate cables, but they will be expensive relative to the cost of the used terminal server itself.

One way to avoid the cost of proprietary cables is to use CAT-5 Ethernet cable with RJ-45M to DB-9F adapters. This will enable you to use any straight through 8 wire cable you happen to have.

Such adapters are [available for less than $2 each|http://www.deepsurplus.com/Network-Structured-Wiring/RJ45-to-DB9-15-25/DB9-Female-to-RJ45-Modular-Adapter-Graybrfont-colorblackAs-low-as-0-61-font]. 

Using that particular adapter with the TS1000, the following illustration shows the necessary pin connections. The colors refer to the colors of the wires in the modular adapter.


''Where more than one wire or pin are shown combined, the choice circled in red worked for connecting to COM1 on a Dell Optiplex 745 PC.''