sundance-communications.com/forum Forums Wiring - Telecom Carriers - Trunks & Services Telecom Service & Providers Analog DID line?

Is there such a thing as an analog DID line? Customers want to have an outside number for each extension without having to pay for an outside line for each extension. I know PRI can do this, but is there a solution for smaller offices?

Yes, analog DID trunks exist. I have seen them used for inbound applications only, most often delivered via a T1 channelbank with an FXO card.

Analog DID trunks are indeed inbound only & they can be delivered stand alone or via T-1. You will need a combination of DID trunks & CO Lines for inbound & outbound service with the corresponding trunk cards for your switch.

DID's are use reverse battery (wink-start) signaling. There would be a DPT card facing the end-user.

It's been a while, but I used Analog DIDs for decades, starting back in the '70s.

They are usually Wink start, but I have seen them delay-dial and immediate start too.

They are a loop trunk with no Dial tone on them. If they're wink start you test them by putting a butt set on them and going off-hook. You should hear the wink as a (double?) click in your ear.

You test your pbx trunk by putting a butt set on them and dialing - USUALLY IN ROTARY.

All analog DID trunks that I ever worked with were either Rotary or MF, NOT DTMF. This was a very common source of problems on Installation. People would order the trunks with "tone dialing" and telco would deliver MF. The only switches I ever saw that could accept MF were COs.

Sam

If an analog DID module isn't available for your PBX, you can always use an adjunct product. MultiTech's CallFinder DID , for example, supports analog DID trunks on the uplink and conventional loop-start trunks toward your switch.

SIP Trunking will do what you are asking BTW if your system supports it.

So, the first question is what system is this going to be used on?

I have heard of some CLECs providing two did service, but have to believe it's via a channel bank. Needless to say the system has to be able to do two also.

Yes there are systems that will do this.

Remember on did analog circuits, you are providing the battery and polarity is essential.

I have also heard of CLECs that provide 2 wire e&m, which only takes 4 wires instead of the 6 with 4 wire e&m. Either way, it's a bidirectional circuit.

John -

I've also used 2W E&M quite a bit (but not recently). The quality wasn't as good as 4W but it worked fine, was cheaper, easier to test and a lot of switches in those days didn't offer 4W BUT did offer the 2W.

Sam