Cisco switch not communicating

We have a Catalyst 2948G-L3 switch as our core switch. On port 12, which is setup to be subnet Subnet mask, we show activity, but anyone who is on that subnet is down. Our setup is copper from the 2948G-L3 to a media converter, from media converter out via fiber to a 3Com edge switch. If I take the 2948G-L3 out of the picture and replace it with a 3Com switch I can access anything on that subnet. I then try to connect from the 3Com to the 2948G-L3 via a crossover cable and I can ping from the 3Com and receive replies, but still cannot on the 2948G-L3. I show links and activity, but still everyone on that subnet has not connection to the network. Not sure how this is possible, but we tried configuring another port on the 2948G-L3, but still nothing.

Thanks for any help.
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can you do a sh int int#/# for us? and change the ip's :)
Did it just stop working or is it recently acquired hardware? If recently acquired is it new or used hardware?
judsoncollegeAuthor Commented:
It actually just stopped working.
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is the port set to trunk or non trunk? (plugging into 3com switch non trunk works) are the interaces no shut?
is there another device w/that IP of the cisco?
judsoncollegeAuthor Commented:
I don't see a no shut on the interface. There is no other device on the network with that same IP.
let me see if I have this right.

computer <> Cisco <> 3com <> users
and if you remove the cisco everything works. but the link between the cisco and the 3 com is not working correctly?
judsoncollegeAuthor Commented:
Our setup is:
      computer <>Cisco<>media converter<>3Com (Edge)<>users

The test we did was to setup:

      Cisco<>3Com (via crossover)<>media converter<>3Com (edge)<>users

      If we plug a laptop into the first 3Com I can ping the 3Com (edge), but I cannot ping the interface of the Cisco. I always have been able to and I still can on the other subnets.

Not sure if I need anything other than sh int12 in the command ou wanted me to type in, but if so please let me know and I will do it. Here is the results of the sh int f12:

FastEthernet12 is up, line protocol is up
  Hardware is epif_port, address is 000d.6501.c012 (bia 000d.6501.c012)
  Description: Routed Interface to Fine Arts
  MTU 1500 bytes, BW 100000 Kbit, DLY 100 usec, rely 255/255, load 1/255
  Encapsulation ARPA, loopback not set, keepalive set (10 sec)
  Auto-duplex, Auto Speed, 100BaseTX
  ARP type: ARPA, ARP Timeout 04:00:00
  Last input 00:00:00, output 00:00:00, output hang never
  Last clearing of "show interface" counters never
  Queueing strategy: fifo
  Output queue 0/40, 0 drops; input queue 0/75, 0 drops
  5 minute input rate 2000 bits/sec, 3 packets/sec
  5 minute output rate 1000 bits/sec, 1 packets/sec
     11816 packets input, 1428362 bytes, 0 no buffer
     Received 5623 broadcasts, 0 runts, 0 giants, 0 throttles
     0 input errors, 0 CRC, 0 frame, 0 overrun, 0 ignored, 0 abort
     0 watchdog, 3708 multicast
     0 input packets with dribble condition detected
     16697 packets output, 1242858 bytes, 0 underruns
     0 output errors, 0 collisions, 0 interface resets
     0 babbles, 0 late collision, 0 deferred
     0 lost carrier, 0 no carrier
     0 output buffer failures, 0 output buffers swapped out
well your test rules out the possiblilty of faulty media so i would think its with the ciscos config. Maybe a faulty port on cisco box?
can you show running config on cisco box plz ?
"If we plug a laptop into the first 3Com I can ping the 3Com (edge), but I cannot ping the interface of the Cisco"

What's between the cisco and the 3com (edge)?  "Cisco<>3Com (via crossover)<>media converter<>3Com (edge)<>users"

Why did you discount the media convert in troubleshooting?
Dear judsoncolleg,

I'll give it a shot.  Check the Cisco the SNMP setting and disable if on.  If this is a used piece of equipment, check the Virtual LAN settings (even if not used).  This would affect the subnet masking.

judsoncollegeAuthor Commented:
Thanks for the offer to help guys. I actually figured it out and it ended up being 2 physical problems. We lost a media converter and the fiber module on the edge switch. I am awarding an equal portion to each of you for taking the time to offer to help.

Glad you got it fixed.
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