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1751 router for VoIP advice

We have a couple of 1751 routers and will get cisco IOS plus for Voip. We will soon install FXS and FXO cards on these 1751 routers. Im just wondering whether the current flash and system memory will cater for the new FXS cards, FXO cards and new IOS Plus.

The routers have the default flash and system memory which is 16MB of Flash memory and 32MB of DRAM memory

Also on that note, will I need to erase the old flash if I have to copy the new IP plus software to the routers ?

Please I need advice.

Community Member

Re: 1751 router for VoIP advice

It depends on the IOS version as to how much memory you will need.

You can take a look at the Cisco IOS feature Navigator to see what version and train of IOS is reccommended for the 1751 for VoIP as well as the memory requirements.

If 16mb Flash and 32mb DRAM are enough memory to use the IP Plus IOS you want, you will probabally have to format the flash when installing the new IOS; It all depends on the memory requirements.

Also, do you have a 1751 or a 1751v? In order to use VIC-FXO, VIC-FXS and other voice cards in the 1751 you will need some DSP modules installed in the 1751. The 1751v models come with DSP's already installed, if it's a 1751 non-v model, then you will also need to purchase some DSP modules.


Tim Medley, CCDP, CCNP

IPT Consultant

Community Member

Re: 1751 router for VoIP advice

I did send the show version of all the 1751 routers we got and according to the supplier of the IP plus IOS, the file is a 6MB file.What do you mean format the flash ? Format the current flash memory and partition to cater for IP Plus ? How do I do that ?

I have 1751 routers.

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