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Walkthrough Wednesdays

Phone in Fallback mode... Available line 0 ???


I have an issue with the SRST on a remote site. We had a network failure, and here is the "show ephone registered" during Fallback mode:

ephone-5[4] Mac:0024.142D.46DD TCP socket:[2] activeLine:0 REGISTERED in SCCP ver 15/9
mediaActive:0 offhook:0 ringing:0 reset:0 reset_sent:0 paging 0 debug:0 caps:8
IP: 51293 7941  keepalive 5 max_line 2 available_line 2
button 1: dn 2  number 5124  CM Fallback CH1   IDLE
Preferred Codec: g711ulaw

ephone-6[5] Mac:0021.A085.5373 TCP socket:[8] activeLine:0 REGISTERED in SCCP ver 15/9
mediaActive:0 offhook:0 ringing:0 reset:0 reset_sent:0 paging 0 debug:0 caps:8
IP: 51777 7961  keepalive 25 max_line 1 available_line 0
Preferred Codec: g711ulaw

As you can see, ephone 5 and 6 are "registered", but ephone 6 has the field "available_line" set to "0".

On the phone, we can see "SRST Fallback Mode Operating" but no line on the phone.

The Network config on the phone shows "Secondary Callmanager: Active"

It's very strange why no line comes up on this specific phone

I already upgrade the IOS on the 2800, it's not better.

Anyone help ?




It's pretty hard to say something without the config info.

Check/increase "max-dn"?

Don't think it's related to this field since I have only 7 ephone and 9 dn on this site...

But here is the "sh call-manager-fallback":

LuxOffice#sh call-manager-fallback
CONFIG (Version=7.0(1))
Version 7.0(1)
For on-line documentation please see:

ip source-address port 2000
max-ephones 30
max-dn 30
max-conferences 8 gain -6
dspfarm units 0
dspfarm transcode sessions 0
no huntstop channel
huntstop channel 0
cnf-file location: system:
cnf-file option: PER-PHONE-TYPE
network-locale[0] US   (This is the default network locale for this box)
network-locale[1] US
network-locale[2] US
network-locale[3] US
network-locale[4] US
user-locale[0] US    (This is the default user locale for this box)
user-locale[1] US
user-locale[2] US
user-locale[3] US
user-locale[4] US
srst mode auto-provision is OFF
srst ephone template is 0
srst dn template is 0
srst dn line-mode single
time-format 12
date-format mm-dd-yy
timezone 0 Greenwich Standard Time
no transfer-pattern is configured, transfer is restricted to local SCCP phones only.
keepalive 30 auxiliary 30
timeout interdigit 10
timeout busy 10
timeout ringing 180
timeout transfer-recall 0
timeout ringin-callerid 8
timeout night-service-bell 12
caller-id name-only: enable
Limit number of DNs per phone:
  12SP: 56
  7902: 56
  7905: 56
  7906: 56
  7910: 56
  7911: 56
  7912: 56
  7920: 56
  7921: 56
  7925: 56
  7931: 56
  7935: 56
  7936: 56
  7937: 56
  7940: 56
  7941: 56
  7941GE: 56
  7942: 56
  7945: 56
  7960: 56
  7961: 56
  7961GE: 56
  7962: 56
  7965: 56
  7970: 56
  7971: 56
  7975: 56
  7985: 56
  anl: 56
  ata: 56
  bri: 56
  CIPC: 56
  vgc-phone: 56
Log (table parameters):
     max-size: 150
     retain-timer: 15
transfer-system full-consult
transfer-digit-collect new-call
local directory service: enabled.
Extension-assigner tag-type ephone-tag.



I got a similar problem:

CUCM 9.1.1a

Cisco 2821 running c2800nm-ipvoice-mz.151-4.M6.bin

SCCP IP Phones 7941 & 7942

My IP phones are registering on VGW, but don't have a line. I tried many loads for the IP Phones (8.5.4 till 9.3.1) and other IOS 12.4.24T on VGW, but still no phones registering with a DN.

Have you found a solution?



Hi David,

       I got the same issue with you. I wonder if you have resolved it ? how to do it ?

      Thanks in advance!

Hi Tom,

If you set an old load, then the phones will have the DN. But the old load will not work with +E.164 numbers, so this was not a solution for me. And Cisco doesn't do any development anymore on those old phones, so SRST is not working as it should...




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