Douglas Krantz - Technical Writer - Describing How It Works
Go to the Writer Home Page of Douglas Krantz -- Describing How It Works
Go to the Fire Alarm Operation Map Page of Douglas Krantz - Technical Writer
Go to the General Electrical Map Page of Douglas Krantz - Technical Writer
Go to the Fire Alarm Description Map Page of Douglas Krantz - Technical Writer
Go to the Fire Alarm Installing Map Page of Douglas Krantz - Technical Writer
Go to the Fire Alarm Maintaining Map Page of Douglas Krantz - Technical Writer
Go to the Fire Alarm Testing Map Page of Douglas Krantz - Technical Writer
Go to the Fire Suppression Map Page of Douglas Krantz - Technical Writer
Offers from Technician's Corner

I have a question about something
Douglas Krantz -- Fire Alarm Engineering Technician, Electronic Designer, Electronic Technician, Writer

I have a Question


I work in a senior assisted living home. I have a question about our Simplex 4005 fire panel. It is showing a "City Circuit Trouble 1". It started after hours and on the weekend.

I was wondering if you could explain to me why it is present or what may be causing this trouble. I know I can't just acknowledge, silence, and reset this trouble as it indicates some problem. But the call center says that they are receiving all communications and not to worry.

The other problem is that the audible tone for the staff and residents it is driving them crazy at this point.

Do you have any advice or help that you could offer?

Signed M H

City Circuit

Older fire alarm control panels (the Simplex 4005 control panel counts as an older panel) sometimes had a "City Circuit" output. The City Circuit was used as a direct means of calling the fire department over dedicated telephone lines. Nowadays, this type of communication is not used, but the card is still there.

To find out more about your City Circuit card, Google the words "Simplex 4005 city circuit", and close to the top will be information about the City Circuit card, and the Simplex 4005.

On the circuit card itself, check the disconnect switches, one of them might be in the wrong position.

Also, there may be something wrong with the card, or another switch somewhere else is set wrong, or a plug has come loose in the panel, but basically, the card might not be working right. To fix the problem, you may have to get the fire alarm system serviced.

When the system is being serviced, if the card isn't being used at all, you might even want to have the card removed. (Don't remove the card yourself because then you can't get rid of the trouble on the panel.)

Annoying Tone

The other thing you mention is the tone that's driving everyone crazy. To communicate alarms and troubles to the monitoring company, it sounds like you have an external box doing the dialing. If so, that box might be making the annoying tone. This is a red box fairly close by, or at least in earshot of the fire alarm panel.

Take my word for it, no one can tell where this tone is coming from. To confirm that you've found it, find the red box and put your ear next to it. Once you've found the box, on the right hand side of it, there may be a small button. Press the button for about 3 seconds and the box will go silent.

That annoying tone is a trouble reminder sound, though. Just to remind you that there's a trouble on the system, every 24 hours this box will turn on the tone again. To silence the red communicator box permanently, you will have to fix the trouble with the Simplex 4005.

Call Center

Keep in mind also, the call center doesn't receive a continuous trouble signal. They only receive a one-time signal that says there's trouble. Until all troubles are fixed, they won't receive any other trouble signal.

They are receiving their daily test of the phone lines, so they can tell you that part of the fire alarm system is working. However, beyond receiving the one-time turning on or off of the alarm, supervisory, and trouble signals, they can't tell if there's anything wrong with your system. That probably explains why they don't think there's a problem.

Douglas Krantz

In the book "Make It Work - Conventional Fire Alarms" by Douglas Krantz, I'd like to show you how the fire alarm system works. The book describes the basic fire alarm system. Order Here

More Articles

Is the Fire Alarm Control Panel Necessary? -- Having detected a fire, a fire alarm system sounds the alarm. Other than the building wires that carry the signal from the fire detector to the fire horn, everything else in a fire alarm system ... Read More

I have this subject panel made by a company As Built -- I have a fault on the panel saying battery charger. I am unable to find the part for this panel. Can you help? ... Read More

How Can We Fix Intermittent Beeping Troubles? -- We have a fire alarm system installed ~ 2000, it started beeping trouble, runs through all the points as troubles, then restores to normal. Fire alarm technicians cannot figure it out. Read More

What is Smoke Power on a Fire Alarm Panel? -- 2 Wire Smoke Detectors are connected to the Zone Inputs of a conventional Fire Alarm Control Panel (FACP) , and so too are 4 Wire... Read More

Post this by your fire alarm panel -- It shows the in-house fire alarm system and how it calls the fire department.

This website uses cookies. See Privacy for details.

Get the book Make It Work - Conventional Fire Alarm Systems

Get help finding ground faults

I receive commissions for purchases made through links in this post