From the following output what does the DSX1 means? Thanks!!
router#sh int Serial0/1/0:15
Serial0/1/0:15 is down, line protocol is down
Hardware is DSX1
MTU 1500 bytes, BW 64 Kbit, DLY 20000 usec,
reliability 255/255, txload 1/255, rxload 1/255
Encapsulation HDLC, loopback not set