Gateway to Gateway Analog Circuit Type

[patrick.hurley]

Which type of connection is best for gateway to gateway analog connectivity? FXS to FXO or E&M to E&M?

I am not going through the PSTN but connecting two Cisco gateways together as in a tie line configuration.

[Aaron Harrison]

E/M - E/M will give you more options (like passing numbers) than FXS/FXO...

[wojtek]

Hi

FXO is able to receive caller ID, and FXS is able to send it (using FSK). It works for H.323 gateways (not for MGCP). So best way is to connect routers back to back using two lines, and two interfaces (one fxo, one fxs in each router). Then you can configure your gateways to use FXS port for outgoing calls, and fxo for incomming and Caller ID should work in this configuration.

It is more expensive than using E&M card.

Best way is to connect routers back to back using ISDN BRI interfaces (one as a user site, one as a network), but you ask about analogs.

Regards

Wojtek

[patrick.hurley]

I didn't think about ISDN BRI for voice calls. Are there any reference documents? Now that I think about it, I am just going to use a VWIC with some DSPs and make it a PRI.

[wojtek]

Hi

It depends how many concurrent calls do you plan between your routers. If more than 4 it is better to use PRI, if less BRI. But it is obvious that ISDN interfaces will work better than analogs.

BRI interface in one router you configrue as a user site, in the second as a network site, and it works. You must also prepare a special cross cable for BRI.

Look at:

http://www.cisco.com/en/US/partner/products/hw/modules/ps2641/products_installation_guide_chapter09186a008007cb4c.html#wp1023902

for PINs on RJ-45 connector used for TX/RX.

I hope that his help, if yes rate my post ;-).

Regards

Wojtek