E1 from SDH MUX

The SRW224p seems to be an ethernet switch, it doesn't have an E1 interface.

If you have an E1, you need a router with an E1 interface to terminate it.

A MUX in general is not a router, it usually takes a higher speed line (ie. E3) and muxs/demuxs it down to individual E1s. Also, maybe your telco already installed a router there as well?

You probably want to ask whoever gave you the E1 what you need for it, just to make sure, but if you really do have an E1, you probably need something like a cisco 1841 with a VWIC2-1FMT-T1/E1 or many other configurations of routers with E1 interfaces..