ATA186 VOIP Adapter. What Will I Hear?

[richardfs]

My assigned mission, and having no option to accept or decline, is to adapt the software for a security system to use the ATA186 to make contact with a central office. The system currently uses the PSTN to place its call. The problem is that I will have no ATA186 to test with, and the 186 is going to be configured by the end customer to use Private Line Automatic Ringdown. So my questions here are to those kind people who have experience using this device configured in this way.

1. The security system *has* to dial *some number*. If no number is programmed for it to dial, the call is not placed. So, the question is, will it upset the 186 if the security system sends 1 or more DTMF digits while the 186 is itself attempting to make a connection? I understand that the 186 can be programmed to wait n seconds prior to "dialing", and I can delay the sec system from doing its own dialing until after the programmed delay in the 186. Will that work?

2. As I said, the 186 will be programmed to wait n seconds prior to making its connection. When it "dials", will the number it dials be heard through the POTS interface. This is important since the sec system will be or could be in a mode to listen for incoming DTMF from the central office, and I need to know if we will get a preliminary string of DTMF digits prior to our ultimate connection.

Thanks in advance to anyone who can answer these questions.

[christopher.l.lawson]

I have experience using ATA-186s with alarm panels that dial into a central receiver, but not using plar for the dialing. By plar, I assume you are talking about setting up the dialplan settings to digits and automatically dial after n-seconds. Why wait at all? You may find the alarm panel won't talk until after it thinks it's dialed and heard the 'speak-now' dtmf tone from the CO.

You didn't mention what firmware (h323, callmanger, etc). For H323 and CM loads, I think the ATA will ignore the extra digits if it is still dialing/connecting. You can alter the settings on the ATA that affect DTMF passthru, but I'm willing to bet that the alarm system passes DTMF tones to the central office receiver. Most alarm systems use dtmf to send codes as it's reliable and very tolerant of phone line quality. Ours do, and I've figured out all the codes by using the nprintf feature of the ata to watch all the dtmf codes sent/received.

-Chris

[christopher.l.lawson]

http://www.cisco.com/en/US/customer/products/hw/gatecont/ps514/products_administration_guide_chapter09186a00800c4b8f.html#1080432 gives an example is setting up PLAR. It calls it a hotline, or warmline depending on whether it dials immediately or waits for other input.

The examples given were:

Example 1: H05551212 (Hotline configuration; the Cisco ATA immediately dials 555-1212 when the handset goes off hook.)

Example 2: H55551212 (Warmline configuration; the Cisco ATA waits for five seconds and dials 555-1212 if no digits were entered when the handset went off hook.)

-Chris

[richardfs]

Thanks for your reply Chris.

"Why wait at all?" What I'm thinking is to have it wait 2-3 seconds before dialing so that the alarm system can periodically pick up the line and listen for a dial tone, then hang up prior to the ATA triggering its connection sequence. We want to have some indicator produced by the alarm system if the network is down... and I'm assuming I would get no dialtone in such a case.

I wrote the software for the alarm system so I can make it do pretty much whatever I want. But what I really want is to keep my software changes to the bare minimum. This is why I want to know if I can have it dial a single digit after the ATA has done its thing. That would minimize the changes I would need by a great degree, since the indicator as to whether or not the alarm system uses a phone or a radio is dependant on if there is a number programmed for the number-to-dial. If there is, then we use a phone. It would take more than I want to do to change this method. Also I need to know if we will hear the ATA dial out so I can screen this DTMF from being interpreted as coming from the central office. (Yes, so it won't be understood as the "speak now" DTMF tones.)

The end customer wants to use PLAR so that he can control the call destination without having to define this in the alarm system.

And yes, the alarm system uses DTMF codes to define the alarm type, location, and other control codes ... but the customer is getting location info via the ATA's IP# (I think).

One thing that is helping to complicate matters a little is that we want the same software in the alarm system to be usable for both the ATA and PSTN.

[christopher.l.lawson]

Ok, I think I understand. When you use the dialplan to add digits or do a hot/warm line, the analog device attached to the ATA will not hear the extra tones. The other half of the question that I was trying to answer before, was whether the central office would hear the extra any digits added by the alarm. I don't think so, provided they are dialed before the connection goes through.