Interworking problem using the NM-8AM modem module

[SteveNZ04]

Hi My company is currenly attemptng to replace an aging USR modem bank for one of our dial-in services, but the proposed solution which we are implementing namely the NM-8AM modem module will only successfully work when the end user dials in using a modem setting of 8N1 (8bits, No parity,1 stop). Currently all our existing customerbase are set up for 7E1 and there is no way we have been able to re-configure the NM-8AM to work successfully with these connections. We cannot get the customer base to change, We need to be able to configure the modem bank to work in this mode. Any suggestions?

[makchitale]

Since the NM-AMs are internal modems, databits/ parity/stopbits commands are no-ops on NM-AM (because NM-AM lacks a UART to handle the async framing parameters). The correct way to do so is by using a modemcap.

By default, the configuration is locked to 8 bit data, no parity, 1 start, 1 stop bit, and normal mode connections.

-O (O for Oscar)is used to set the parity bit, please refer to the link below:

http://cisco.com/en/US/products/sw/accesssw/ps4455/prod_command_reference09186a00800f48f6.html

conf term

modemcap edit 7e1 miscellaneous &f-O1

line x y

modem autoconfigure type 7e1

Thanks, Mak

[SteveNZ04]

Hi Mak

Thanks for the advice.... My Technical SME has now done this and we still cannot establish a connection the works when the client end comms is running 7E1 but works OK when 8N1.

A further comment from one of my SME's is "O1 would appear to only set the serial port parity - we require to set the line parity". I don't profess to understand what he means by this but maybe you could comment?

Would a mica modem bank NM-6DM be any better? Can you confirm if we would have to provision an E1 or T1 PRI to connect to these and that analogue 2 wire lines cannot be connected straight into this module like you can with the NM-8AM

Steve

[SteveNZ04]

Another issue we have is that the Cisco online documentation for the NM-8AM quotes it using Microcom modems. My SME tells me that the configuration points to it being a Conexant Smart-ACF modem. Is there any explanation for this?

cheers

Steve

[makchitale]

Looks like we have a NM-8AM-V2 or even called NM-8AM-ENH (enhanced) which are similar to the WIC-xAM, these modules are a replacement for the NM-xAM which is end-of-sale/ end-of-life. The newer cards have the Conexant chip (where as the older ones were the Microcoms)

http://cisco.com/en/US/products/sw/iosswrel/ps5207/products_feature_guide09186a00801f129e.html

Referring to my previous posting that said “Since the NM-AMs are internal modems, databits/ parity/stopbits commands are no-ops on NM-AM (because NM-AM lacks a UART to handle the async framing parameters). The correct way to do so is by using a modemcap.”

A bug/feature request was filed (CSCdt00123) to make the IOS not accept commands such as databits and parity for modem modules that do not have an onboard UART.

NOTE: the NM-AM-V2 in fact has an UART (the NM-AM doesn’t) so line parity/databits commands are necessary to set async parity framing - they do not have AT commands for this. It appears that the WIC-xAM / NM-AM-V2 modules were erroneously included in the fix for CSCdt00123.

Ideally we should be able to add the commands under the line:

router(config)#line 1

router(config-line)#databits 7

router(config-line)#parity even

and not see this output “This command has no effect on this line; use modem AT commands instead”

CSCee60088 has been filed to fix this issue but is not yet resolved. IOS images prior to 12.2(8)T / 12.2(11)T should work fine, however NM-AM-V2 supports starts from 12.3(4)XD / 12.3(7)T so the work around of using a previous image will not help here (is ok with the WIC-AM).

Please open a TAC case with the info provided.

Thanks, Mak

[SteveNZ04]

Thanks for this Mak.... Yes I've confirmed we have the V2 model so I'll get my technical guys to follow your recommendation and get a TAC case open.

Regards

Steve

[makchitale]

I just checked the engineering specs & see that the V2 is UART less & will need AT commands for the parity/databits. Do not see any documentation on the same. Opening a TAC case will help (that way can get some info from the developers).

Thanks, Mak

[SteveNZ04]

TAC case open "600294143 configuring 7,E,1 support on NM-8A-V2" Being looked at by Cisco Systems TAC, Sydney, Australia. Really appreciate the help you have provided in this.

Steve

[makchitale]

CSCef05828 "NM-AM-V2 does not support parity" has been filed to track/resolve this defect.

Thanks, Mak

[SteveNZ04]

Hi Mak

We have 90% resolved the problem now.... Cisco finally resolved the 7-E-1 situation which gave us a perceived 90% customer usage but we still some customers using 7_E-1 who still cannot synch up to the cisoc modem bank. It appears that we have a speed issue on our config. Again its not a question of working quicker, we want to make the modem bank work SLOWER as a lot of the applications that dial in are old paging apps that transmit at 300 Baud. It seems that we can't config the Modem bank to go that slow.

This below is from the module, can you advise any further commands that need to be input to make it run as slow as 300 baud (V21 modulation).

Regards

Steve in NZ

Here is the CHAT Script.

chat-script CONN ABORT ERROR "" "AT&F\\v1S0=1E0Q1+MS=V22B,1,1200,2400,1200,2400" "" "ATA"

chat-script AMS ABORT ERROR "" "AT&F\\v1S0=1E0Q1+MS=V22B,1,1200,2400,1200,2400&W"

[laurienz04]

Hi - I would like to add to SteveNZ04's message

We currently use a bank of 8 US Robotics - Total Control NetServ 8/16 V34 Modems to provide dial in access to send SMS to cellphones. Callers use paging applications ie: Airsource Lite 1.7 set at 1200 baud 7 data bits, even parity and 1 stop bit.

We have just installed a second bank of 8 Cisco modems as described by Steve which do not not work for all of our customers - I have included the initialisation strings for the both types of modems -does anyone know how were can replicate the string used for the USR modems in the chat scripts that we currently have set up for the Cisco modems and provide information about the meaning of the various fields in these chat scripts please ?

Regards

LaurieNZ04

Cisco SMS Modems -

chat-script CONN ABORT ERROR "" "AT&F\\v1S0=1E0Q1+MS=V22B,1,1200,2400,1200,2400" "" "ATA"

chat-script AMS ABORT ERROR "" "AT&F\\v1S0=1E0Q1+MS=V22B,1,1200,2400,1200,2400&W"

-------------------------------------------------------------------------------

chat-script CONN ABORT ERROR "" "

AT&F\\v1 S0=1 E0 Q1 +MS=V22B,1,1200,2400,1200,2400" "" "ATA"

&F\\v1 …….. not sure what \\v is – the rest may be factory defaults ???

S0=1 …… Auto Answer after 1 ring

E0 …... stops the modem echoing any commands from xmhs20 when running

Q1 …… makes the modem "quiet" ie it does not say RING, or CONNECT etc

+MS=V22B ……. possibly setting modem speed to V.22bis 2400 baud ???

1

1200

2400

1200

2400

ATA

--------------------------

chat-script AMS ABORT ERROR "" "

AT&F\\v1 S0=1 E0 Q1 +MS=V22B,1,1200,2400,1200,2400&W"

AT

&F\\v1 …….. not sure what \\v is – the rest may be factory defaults ???

S0=1 …… Auto answer after 1 ring

E0 …... stops the modem echoing any commands from xmhs20 when running

Q1 …… makes the modem "quiet" ie it does not say RING, or CONNECT etc

+MS=V22B ……. possibly setting modem speed to V.22bis 2400 baud ???

1

1200

2400

1200

2400

&W ……. write to memory

-------------------------------------------------------------------------------

US Robotics SMS Modems -

======================

The current script file has the following initialisation string -

AT &F1 E0 Q1 &G2 S19=1 S27=1 where

&F1 loads the factory defaults number 1

E0 stops the modem echoing any commands from xmhs20 when running

Q1 makes the modem "quiet" ie it does not say RING, or CONNECT etc

&G2 sets 1800 Hz guard tone for 1200 and 2400 b/s connections

S19=1 set an inactivity timer to 1 minute this must always be set as xmhs20

is not smart enough to hang the modem up after a call

S27=1 enables ITU-T V.21 modulation for 300 b/s

NetServer Support

Support for the NetServer modems can be contacted by e-mailling

APR_Technical_Support@3com.com or calling 0800 446 398