I am trying to DIY why a phone on my TDA50 stopped working after a technician did an alarm service call. 3 phone (non Panasonic) tech have been out and cannot find the problem.

The phone in my study stopped working. There is a red line on every other phone like that phone is in use.

I have done the following:

Swapped the phone between another station the phone works at the other station and when pugged into the PBX. I have tried plugging in another phone in the study with no success. While the phone is using pins 3&4 on the -11 connector, this line uses pins 2&5 when connected to the PBX.

I have disconnected the line from the phone and the PBX and checked the continuity and the line does not show a short. I have pinged the line from the phone jack through the terminal blocks and I get a strong tone when it is disconnected from the PBX. I have disconnected the line from the PBX and the phone. Tested the line with a 9 volts battery and I get a strong 9 volts on the meter.

I swapped the connector at the PBX with another location and the other phone (Bedroom) shows a red light on all of the phones, but the phone in the bedroom works. But the phone in the study does not work. So the terminal on the card is fine.

SO;

The phone works
The line seems to be ok from the phone, through the terminal blocks to the PBX.
The card seems to be fine.

What am I missing?

Thanks in advance for the help.

R

One other point There is a 4 pair cable from the phone to the terminal block. I swapped between the b/bw and the g/gw pair just to check. I checked from the connector back to the pbx and the wire checks out.

On the KSU, there are 4/8/12/16 ports. Take the phone and plug it in directly to the proper slot (ie pretend by default they are numbered 101-112). Does it work? If it does, you have a cabling problem. If not, then it's either the phone or programming.

Carl

This "little job" my wife has assigned me has taken a life of it's own. I have chased the wires from the port on the TDA50 (2 pair) to the primary wiring block, where a single pair travels to an adjacent wiring block, then to a wiring block in the garage before it terminates at the connector at the wall.

Because of my frustration, I have used my LAN chaser to verify I have the correct wire pair from both sides(from the TDA50 and from the phone). I have checked the single pair and it does not have a short, plus it passes voltage fine. I have replaced the connectors at the TDA50 and at the wall plate.

What purpose does the center pair serve from the TDA50 server? This pair seems to terminate on the block. I notice this is true with the other lines coming from the TDA50.

It makes sense that there is a issue with the wires, as the phone works at the TDA50, I can swap a line and that phone works at the port. But what does not make sense is the wire pair check out from connector to connector. This is the issue I have had with the techs I have had out, ever thing checks out individually, but the phone does not work.

Thoughts on another way to check the wiring?

Thanks again for the help.





Thanks again for the help.

R

The first 4 station ports on a TDA-50 are hybrid ports and all 4 wires are active, center pins for the 4 analog stations and 4 outer pins for the digital stations. The cables I use are two pair umbilical cords (4x10) designed for the TDA/TAW from OMI electronics in FL. Every station I wire uses at least two pairs so when the customer wants one of those "other" digital systems the jacks are already wired. I just run a single pair jumper from the 2nd pair of the KSU block to the 2nd pair of a jack in the house blocks.

So, the count to the garage might be pairs 1-6 are 6 digital stations, you just run those single pairs to the 2nd pair of each house cable and you will get a digital station. It's not that difficult, but I'll bet you wished you had used two pair crossconnects :-)

Carl

Sometimes you just need a new wire.

Put a jack on each end of 100 ft of cable and test if phone works.
Port could be bad with low power, work at KSU but not able to power over length of cable?

uses 3 and 4 at KSU also, unless XDP is off.

Noting what ports are for hybrid and analog depending on your phone type - digital or analog.

Also from the info above - your cable is fine, replace the phone jacks. Just use a 4-PIN code. Have experienced this before and sometimes the pins in the phone jacks for some reason get out od position - misalignment, shorting from within the phone jack.