Batboard

Hello All...

Looking for a bit of help here. Has anyone had luck successfully integrating the external Phone interface option into a typical multi line commercial system such as a Nortel Networks T7208. I know that all I really need to do is bring the receivers TX pair and RX pair into the appropriate pins on the interface module in the console...but I need something that will give me the "off hook" sense also....not to mention what do I do with the receiver...that would still need to be taken "off hook" to activate the phone as well...right???

See below for pinouts

External Enhanced Full Duplex Phone Interface CP0060 (Option Code CTH)
This optional interface includes a telephone interface board. It allows connection to an external telephone
unit, such as a 911 phone, and adds inbound phone call capability, phone patch, and radio patch. Refer to
Table 17 for the pin description of the external phone interface connector.

Table 17. External Phone Interface Connector Pin Description

J400

Pin #* Description
1 Off-Hook Sense
2 Ring Mute Contact Closure
3 Handset TX Audio
4 Handset RX Audio
5 Handset RX Audio
6 Handset TX Audio
7 Ring Mute Contact Closure
8 Off-Hook Sense
*looking into connector, pin 1 is on the left

To activate the off-hook sense, pin 1 (or pin8) should be connected to a 3–12 V dc source. When pin 8
(or pin 1) is grounded, the off-hook sense is activated. When activated, the console either automatically
takes the phone off-hook (if possible) or provides a ringing indication that an off-hook request is being
made. The ring mute provides a closure across pins 2 and 7 to deactivate an external ringer when the phone is
accessed.

Is there some sort of a buffer or interface electronics (such as gai-tronics common audio accessory box XAAB002A or a Plantronics Interface) that I would need to also integrate to get this to function properly...or do we need to go back to the drawing board and look into a new phone terminal itself...meant for PSAP use?

ANY help would be appreciated! Thanks!

We've used the DSI-375 from DEES to provide an off-hook indication for various digital PBX phones:

http://www.dees.com/html/DSI375.html

It'll do a lot more too, but gives a nice relay contact closure for off-hook.

Todd

Thanks Todd......Looks like exactly what I need...in fact when I went to the PD tonight I saw that most of the other phones were indeed meridian....those nortel workstations must be newer add-ons!

I am by no means a phone GURU..so maybe you can answer this one as well. Following this logic...now that I have the "off hook" relay closure issue taken care of to jump the above pins...the console will appropriately route the selected audio from the headset to the "select" speaker on the console and replace the headset with phone audio if I am correct. My next question is wheather or not I can use the headset jack on the phone to get my TX/RX pairs from the phone to the console, yet still leave the actual handset connected to be used as a backup.

Finally, are the meridian series phones able to be put in an "off hook" status while the handset is still in the cradle? I would assume so as they have headset provisions and according to the documentation FEATURE + 72 answers a call.....can that be programmed into a one touch "answer" button?

Thanks again for any info you have!

Don

I have an update to this post:

I was informed by the phone guy that what we actually have at the PD is a Norstar Key System.....not a meridian business set. He says that the above converter won't work with that system because it is all digital (serial) data going to the phones. Does anyone have experience with this style of phone system and integration with a console? There must be a way to get an "off hook" indication.....or is my phone guy just not familiar with this sort of integration.


Any help would be appreciated!