USR 56k Modem V.92 Connects at 9600

[m.zaim]

Hi

I have Cisco 2600 RAS i have configured NM-16A Module with External USR 56K Modems. I can connect but i get speed of 9600..

Can any1 help me with modemcap ???

Configuration is as Follows

interface Loopback1

ip address 192.168.1.1 255.255.255.0

interface FastEthernet0/0

ip address 10.0.0.1 255.255.255.0

interface Group-Async1

ip unnumbered Loopback1

dialer in-band

dialer idle-timeout 600

dialer-group 1

autodetect encapsulation ppp

async mode interactive

peer default ip address pool Cisco2620-Group-1

encapsulation ppp

ppp authentication chap

group-range 33 48

ip local pool Cisco2620-Group-1 172.16.0.1 172.16.0.100

ip classless

ip http server

access-list 1 permit any

dialer-list 1 protocol ip list 1

line con 0

line 33 48

speed 38400

modem InOut

transport input all

autoselect ppp

line aux 0

line vty 0 4

password password

login

[tepatel]

First, add command "modem autoconfigure discovery" command under the line 33 48. After that enable a debug "debug confmodem" and then issue "clear line x" where x is the line number where usr modem is connected.

That way 2500 will try to detect the modem on the line and apply required init string.

Now if you want to apply init string manually, here is the link which talks about init stings and how to apply that

http://www.cisco.com/en/US/partner/tech/tk801/tk36/technologies_tech_note09186a008009428b.shtml

[m.zaim]

Thank you,

But as soon as i enter "modem autoconfigure discovery" command the router crashes with following information:

Unexpected excP0

T8

Writing crashino:3write1 8288 bytes s9 environment write

Qgenvironment writeenviron

*** System received a SegV exception ***

signal= 0xb, code= 0x100, context= 0x80d704bc

PC = 0x208, Vector = 0x100, SP = 0x80005f54

[m.zaim]

btw below is my router show ver:

Router#sh ver

Cisco Internetwork Operating System Software

IOS (tm) C2600 Software (C2600-C-M), Version 12.2(24), RELEASE SOFTWARE (fc1)

Copyright (c) 1986-2004 by cisco Systems, Inc.

Compiled Wed 28-Apr-04 15:30 by kellmill

Image text-base: 0x8000808C, data-base: 0x809917F0

ROM: System Bootstrap, Version 11.3(2)XA4, RELEASE SOFTWARE (fc1)

Router uptime is 18 minutes

System returned to ROM by error - a SegV exception, PC 0x208

System image file is "flash:c2600-c-mz.122-24"

cisco 2620 (MPC860) processor (revision 0x101) with 20480K/4096K bytes of memory.

Processor board ID JAB03300309 (2573950524)

M860 processor: part number 0, mask 49

Bridging software.

SuperLAT software (copyright 1990 by Meridian Technology Corp).

X.25 software, Version 3.0.0.

TN3270 Emulation software.

1 FastEthernet/IEEE 802.3 interface(s)

2 Low-speed serial(sync/async) network interface(s)

16 terminal line(s)

32 bytes of non-volatile configuration memory.

8192K bytes of processor board System flash (Read/Write)

Configuration register is 0x1822

Router#

[makchitale · Accepted solution]

From your setup it does not appear that you are going to need to use the V92 feature on this USR.

Disable the v92 feature (+PIG=1) & then added this init string at&f1s0=1&c1&d2&a1&w (first test with one modem).Reverse telnet to the USR external modem (if the calling modem is a USR modem then do same for it too). Have dip switches 3 & 8 down / rest up.

Router# telnet 192.168.1.1 2033 (where 192.168.1.1 is IP address of Loopback1 & we are making changes to modem connected on line 33 (2033)

at

OK

at+PIG=1

OK

at&f1s0=1&c1&d2&a1&w

OK

Press <6> together & then press to exit telnet session. Make a test call now into the modem attached on line 33.

Thanks, Mak

[m.zaim]

Thanks Mak,

With current configutations added to the modem users can connect at 33600, but the connection drops out after 10 min , 15 min not stable connection.

Thank you again

[makchitale]

We will need to see thru debugs why the connection drops after some time in operation. Basically will need to see who drops the call, the 2600 RAS or the telco side.

deb modem / deb asyn state / deb ppp nego

With the call connected what do you see in “show dialer interface async x” where x is the line/interface number where the call is connected.

Just to be sure that it not the idle timeout that is disconnecting the call, add the following command:

conf term

dialer-list 1 protocol ip permit (instead of using the thru the ACL)

Thanks, Mak

[m.zaim]

thanks again Mak..

Well i have used this modem cap "&F&D2S54=16584S0=0S29=12S21=15S62=8S63=3S34=18000S40=10S10=50" and i have stable connection at 33.6.

How do i get 56k speed or better performance? I am using external US Robotics modem which support v.92 .

[makchitale · Accepted solution]

Can you please confirm that you are using this modemcap on the 2600xm that has external USR modems connected?

If I understand correctly (based on previous postings) we have a c2600xm with external USR modems connected on the NM-16A. NOTE; The USR modems are connected using a POTS line (analog line); if the client modem too is connected to a POTS line when making a call into the 2600xm then we can best get a v34 modulation (more than one A(analog) to D(digital) conversion). However if we have modem maybe on an Access server connected through a T1/E1 line then we can connect at v90 modulation.

Thanks, Mak

[m.zaim]

Thanks Mak....

I have configured 11 modems on the 2610 router i can dialin in any of the modems. It is working fine but, when i say sh users i see sometimes 5 modems as Auto Configured and rest dont come in the list. I can see all the async interfaces as well ..

Please help ...