[nsp] Connecting Max6000 with Cisco 2500 over HDSL: "line protocol is down"

[Mehmet Ali Suzen]

Dear List,
We are trying to establish a connection between Cisco 2509 over a
serial line and HDSL modems to Ascend Max 6000, but frustrated
to get "line protocol is down" status.

Set up is :

  Cisco2509--serial 0
    <----over DTE Cable--V35>
  Alcatel HDSL
     <----telco over line L1 L2 ---->
  Alcatel HDSL
    <---G703---RJ48--->
  E1 port Ascend Max 6000


But we can not ping to serial 0 even modem lights indicates
connection is OK? Shall We assigned an IP address to
serial 0 and WAN interface of Ascend Max 6000 as we did?
What could be the reason to get "line protocol is down"?

Many thanks for any comments or suggestions

Best,
-Mehmet

PS:
Encapsulation has set to be PPP, here is the running conf for
serial 0:
!
interface Serial0
 ip address 192.168.1.60 255.255.255.224
 encapsulation ppp
 ppp authentication chap
 ppp chap password 7 1248574446
!

Here is the status of interface
# sh int ser 0
mahir-r2#sh interfaces serial 0
Serial0 is up, line protocol is down
  Hardware is HD64570
  MTU 1500 bytes, BW 1544 Kbit, DLY 20000 usec,
     reliability 255/255, txload 1/255, rxload 1/255
  Encapsulation PPP, loopback not set
  Keepalive set (10 sec)
  LCP Listen
  Closed: CDPCP
  Last input never, output 00:00:08, output hang never
  Last clearing of "show interface" counters 00:09:36
  Input queue: 0/75/0/0 (size/max/drops/flushes); Total output drops: 0
  Queueing strategy: weighted fair
  Output queue: 0/1000/64/0 (size/max total/threshold/drops)
     Conversations  0/1/256 (active/max active/max total)
     Reserved Conversations 0/0 (allocated/max allocated)
  5 minute input rate 0 bits/sec, 0 packets/sec
  5 minute output rate 0 bits/sec, 0 packets/sec
     0 packets input, 0 bytes, 0 no buffer
     Received 0 broadcasts, 0 runts, 0 giants, 0 throttles
     0 input errors, 0 CRC, 0 frame, 0 overrun, 0 ignored, 0 abort
     119 packets output, 2261 bytes, 0 underruns
     0 output errors, 0 collisions, 31 interface resets
     0 output buffer failures, 0 output buffers swapped out
     0 carrier transitions
     DCD=up  DSR=up  DTR=up  RTS=up  CTS=up