I would like to phase out the 36x0. I check the cisco web site, there is no any router product between 38xx - 72xx. Why?
As Arul has said EOS = End of Sale. This is the date that Cisco stop selling that particular hardware. It doesn't mean support for the hardware has finished but the final support date is usally announced when the EOS notice comes out.
POS - Packet Over Sonet
EOS - End of Sale
*Pls rate if it helps*