So you wanna upgrade your 3620…admin | Friday, April 23rd, 2010 | 1 Comment »
So you want to upgrade your Cisco 3620 but you don’t have an available ethernet port? You can do it the slow way via console connection or you can get a little clever, depending on what modules you have.
For me, I needed to upgrade my router to the last and final supported version of 12.3(26) but the 3620 does not come with ANY ethernet/fastethernet ports. So what to do?
My 3620 has a NM-4T module which is a module with 4 high-speed serial ports.
I connected one serial port off the 3620 to my 2511 router which has a built in serial port AND an ethernet port. The ethernet port is actually an AUI port with an ethernet transceiver.
My TFTP server is connected directly to this transceiver which then allows me to have access to the 3620 through the serial ports.
The 3620 and 2511 are connected via DTE/DCE crossover cables (v.35) using HDLC as the WAN protocol.
Simply configuring a couple static IP addresses on each interfaces as well as one static route on the 3620 and we have connectivity!!!
So next time you want to avoid using the slow console port, there are other ways to get that IOS onto your router!