dial-up Modem with VG224

[robin99]

I need to setup a remote access for troubleshooting my user's PC and the only access I can think of is using VG224 with modem passthrough but I couldn;t find the document in cisco.com. The setup will be as follow:

PSTN -- 3825 -- LAN -- VG224 -- dial-up modem - PC1.

I am not sure if VG224 allow remote access functionality for the above setup and what is the highest speed it supports. Anyone can help? thanks

[ebreniz]

You can have speed upto 33.4kbps with VG 248 with G3 modem settings.

http://www.cisco.com/en/US/tech/tk652/tk777/technologies_tech_note09186a00801e61bb.shtml

http://www.cisco.com/en/US/products/hw/gatecont/ps2250/products_configuration_example09186a008020160d.shtml

[anup.anand]

Yes, VG224 supports modem passthrough and once the connection is setup, the functionality is transparent. You could use it for remote access or as a backup link etc.

http://www.cisco.com/en/US/products/hw/gatecont/ps2250/products_data_sheet09186a00801d87f6.html

In passthrough mode, the gateways would switch over to G711 codec and you should get 64K bandwidth for the call. So if you use V.90 modems, you can go upto 56K.

You would need to setup both 3845 and VG224 for modem passthrough. See this link for modem passthrough configurations.

http://www.cisco.com/en/US/products/sw/iosswrel/ps1834/products_feature_guide09186a008008024f.html

Thanks,

Anup

[anup.anand]

Regarding the modem speed, let me correct myself.

Just saw this note in the IPT SRND,

V.90 Support

Currently, Cisco equipment supports only V.34 modems. Although V.90 modems will function on existing hardware, and speeds higher than V.34 speeds can be achieved, full V.90 support cannot be guaranteed.

Thanks,

Anup

[robin99]

thanks for your reply. Can you point me to Cisco weblink or page in SRND that stated on VG224..."Although V.90 modems will function on existing hardware, and speeds higher than V.34 speeds can be achieved, full V.90 support cannot be guaranteed"? I really need to show it to my customer. thanks

[anup.anand · Accepted solution]

Check this pdf file. Page 4-20 V.90 Support.

http://www.cisco.com/application/pdf/en/us/guest/netsol/ns268/c649/ccmigration_09186a0080479538.pdf

Please note that this is a generic statement. Doesn't specifically say about VG224.

Regards,

Anup

[robin99]

Thanks for yiur kind info. I have got what I want.

[anup.anand]

Got a chance to test this out today. We tried using modem passthrough. Set up the modems to V.90. Hooked up two gateways, a VG248 and a 2620 over the LAN and even under the most favorable conditions (<1ms delay and no packet drops), it connects using V.34. Looking at the modem lights, I can see that it tries to use V.90 first, but then will fallback to V.34.

Also tried over a WAN (link speed 64K and 128K - avg delay 45-55ms and some packet drops as well). It takes multiple tries before the modems connect. They get connected at V.34, but the calls get dropped after a couple of minutes.

HTH

Anup