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How to replace analog lease line with another cost effective medium


My situation is this. We are currently subscribing to over 60 analog 4-wire leased lines to different remote sites from our central office. The analog leased lines are used to carry audio traffic from central office's controller to remote sites' analog 4-wire transmitter. Both the controller and transmitter are equipped with analog interface port for the 4-wire leased line.

We have been given 6 months to move away from the analog leased line by the service provider. We are in a dilemma now as all the options that we can think of are too costly.

I was having the idea of replacing the analog leased lines with POTS lines, assuming it can be done. This would be the most cost effective as I can get a low monthly fixed rate for the POTS line.

Does any have a suggestion how I can do this?

Any ideas are most welcome.


12 Replies 12

paolo bevilacqua
Hall of Fame Master Hall of Fame Master
Hall of Fame Master

What prevents you from doing voip ?

Using voip will be expensive as I have to replace the analog leased lines with digital 64kbps (at least) lines. Analog lines are about 3 times cheaper than a 64kbps line.

Do you think using FXO/FXS card will help? If I have a router with 2-port FXO/FXS card, can I connect one port to PSTN and another port to controller and have both ports loop internally, maybe using connection trunk/plar. At the remote side, I will also have a router with 2-port FXO/FXS card. One port to PSTN and another port to transmitter. Again, both ports are loop internally.

This possible?


Do you have internet access in the remote sites? You can do VoIP over the internet/VPN.

For the 4 wire equipment you need to use E&M cards, FXS/FXO is not applicable unless you also use an hybrid 2/4 wire adapter.

Leo Laohoo
VIP Community Legend VIP Community Legend
VIP Community Legend

I agree with Paolo's comments. Please have a chat with Telekom Malaysia about their IP-related products as this could be cost-effective in the long term plus it's also scalable.

The problem with Malaysia's low-priced (about USD45/mth) Internet broadband is its not stable and based on best-effort (shared-based). We cannot afford to replace the analog leased lines with expensive dedicated Internet lines. It would make our businesss non viable.

About my idea. Do you think the setup below is possible?

Controller -- E/M 1 -- FXS/FXO 1 ---------PSTN --------- FXS/FXO 2 -- E/M 2 -- Transmitter

FXS/FXO 1 calls up to FXS/FXO 2 can gets connected.

E/M 1 (4-wire) is loop internally (maybe using Connection TRUNK/PLAR) to FXS/FXO 1.

E/M 2 (4-wire) is also loop internally to FXS/FXO 2.


Hi, where the routers in the diagram above ?

If there are no routers, how connection trunk,etc could apply ?

I think you need to seek help from the manufacture or controller/transmitter equipment if you want to migrate their equipment from leased to regular pstn lines.

Controller -- E/M 1 -- FXS/FXO 1 ---------PSTN --------- FXS/FXO 2 -- E/M 2 -- Transmitter

E/M 1 and FXS/FXO 1 is in router 1.

E/M 2 and FXS/FXO 2 is in router 2.

The equipment manufacturer of the controller/transmitter is no longer supporting them. It's already obsolete.

And how the routers would decide when to call and when to teardown ?

That doesn't seem a good design, beside, router are expensive.

You could investigate a data plan over GSM, and use appropriate interface in the routers.

The call should always be up. If its down, then the call should be automatically re-initiated. I can get a low monthly fixed rate for unlimited call minutes from our service provider.

Router price is not an issue as it is only a one-time cost.

It may work, still I'm not quite convinced. At least try to get E1 at the center to eliminate the many pots interfaces.

If I have a router with 2 FXO ports, one facing the PSTN and another facing my controller, do you know how I can loop the traffic between the 2 FXO ports?

FXO1 --------- PSTN






FXO2/E&M --------- Controller

It's not a loop, it's a normal configuration with connection plar or trunk, and possibly some translation rule.

Be aware if you never did voice configuration before that may be very frustrating and I recommend you hire a qualified consultant.

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