The Telephone System
The main system unit from BBS Telecom.
System phones have alphanumeric caller ID displays
Purchase and installation
After years of thinking
about it, I
decided to install a phone system
in my home. There were several features I wanted. These included:
- Hands free intercom answer-back.
- Caller ID (Name and Number) Display
- At least one dozen extensions
- System programmable by touch tone phone. This way my home
can can program and configure the system.
The two systems I
considered were by BBS
not have some of the above features, or were available at a large cost.
I therefore decided to use the BBS system, and purchased a IPS416 with
CID from HAS
The system unit was
and system phones cost $180.
The extensions wired are:
In light of the above
considering building my own system.
there is a lot of hardware needed to implement a cross bar switch for
extension, 2 outside lines, 4 intercom conversations, and 2 signal
(almost 100 switches). I would also need to build the hardware for the
signal sources such as the ring and dial tone simulators. All this
to be committed to PC boards (for reliability). I decided this was just
too much work.
In order to prepare for the phone
system I home ran Cat 5 cable to
various rooms in my home that didn't have a phone line. I took the
to also run RG-6 into the bedrooms. The installation of the cable was
by installing a 2" conduit from the attic to my basement through a
chase in my home. I had found this chase while planning the
of my central vacuum system
in my basement (which I finished myself) has a drop ceiling, I could
access the hidden areas of the walls on the basement and first floor.
the installation of the conduit, I was thus able to run cable to any
in the house to the wiring closet in a corner of the house. There the
lines were punched down into 66 type blocks. I then punched the leads
loose RJ11 jacks to the phone lines. These latter jacks allowed me to
the various extensions into the phone system's extension jacks, and
fastened to the side of the 66 type blocks.
- Guest Room
- Master Bedroom
- Master Bath
- Secondary Bedroom 1
- Secondary Bedroom 2
- Secondary Bath
- Kitchen dining area/family room
- Rec Room
- Basement Bath
- Lab/Storage Room
I had previously been
people that prewired their homes,
that such a desirable infrastructure was beyond my reach. I have since
learned that it is just difficult to a varying degree depending on the
design of the house. I was fortunate in my case that it really wasn't
difficult to implement, I just needed the realization that it could be
done. After having installed a wired security system, a central vacuum
system, and this phone system, I have proven to myself that even
homes can be retrofitted for new technology that comes along.
Use of the system
One of the features of
system is the auto attendant. This
allows the installer to record a message instructing the caller to
a number depending on the caller's intentions. My message sounds like
You have reached the home of Agnes and Edward. If you are a
wish to send a fax, or want to leave a message, press '102'. Or else,
on the line or enter '0', and we will answer your call".
Only at this point will
one of the
phones in the house ring. We look
to fewer telemarketer calls interrupting us. If they still ring our
we will just hang up on them, after all, they were warned to leave a
My home automation
computer is now on
its own extension. Since the
node can seize the line, I have programmed the computer to answer the
when its extension rings. I can then use the touch tones to send
to it. This is better than the previous system where the computer
processing tone commands when I enter a password sequence. This
sequence is intended to be an invalid phone number. This prevents the
company from connecting me to an unknown location. However, the phone
answers with a beeping sound to alert the caller this number is
The problem occurs when this beeping interferes with my computer's
to recognize the touch tone command. This no longer occurs since I am
a quiet 'conversation' with my computer on my phone system. I can now
call in from outside and control the home without having to bypass my
machine or without having to disturb any inhabitants in the home.
A nice feature that I
did not expect
is how the unit handles fax
The auto attendant can recognize an incoming fax call and route it to
fax machine. When the fax machine picks up, and hears the fax tone, it
automatically starts receiving faxes. People can now send us faxes
ringing a phone inside the home. They also no longer have to call us
to notify us of an incoming fax.
The Door Phone
Instead of a regular
can install a door phone, which
any person to answer the door by telephone. BBS used to sell
phone unit, but at $180 I decided to go with a third party product
The "DoorBell Fon
is designed to be used with PBX and non-PBX systems, and was installed
on the second incoming line. When a visitor presses the old
button, or the button on the door unit, it causes the phones to ring
the house, and anyone can pick up the phone to speak with the visitor.
When I purchased the
unit, I also
wanted anyone inside the home to
able to connect to the door and speak with the visitor even before
had pressed the doorbell button. However, the unit would not
this action, although this feature was mentioned in an on-line
for the door phone unit (page
is similar to the "hands-free speaker phone" feature of the BBS key
Over the years, we have come to like this feature very much.
it was a problem with my installation, I used the DoorBell Fon in all
of configurations, but finally gave up after a few days. I
and emailed the manufacturer, and to my surprise, a new version of the
microcontroller (it is a PIC) was needed. Paul from customer
sent a new rev to me at no charge. I found phone support to
good, but email
support took a
week before a response was generated.
I installed the new PIC,
and 'bingo' it
worked like a champ.
anyone inside the home can connect to the door at any time to listen
speak by hitting '62' on a phone. I can also call from
home, and connect to the door phone, answering the door when I am at
or on travel. Worthington
had the lowest price at $98. A pdf manual is available here
from smarthome.com. More technical information on this unit
be found with a Google
, or by using the link below.
The Door Phone unit from LocalPlex
Caller-ID display to the IVT-16
The black "IVT" system
phone that is
available from BBS comes in two flavors. The IVT-16D has an
display that displays Caller-ID information (if the phone system has
option), and the IVT-16 (a.k.a. IVT-16N), which has no LCD
display. I purchased
one unit of the latter type from a person on ebay, and decided to open
the unit up to see if a display could be added.
LCD display on the IVT-16D. Apart from basic system status, it also
the Caller-ID information of the caller.
The IVT-16, which has no display. The location of the display has a
black plastic plate.
When this phone is powered up, the 'MEM' LED (top middle) lights up as
a power indicator.
Internal look of the IVT-16D. The LCD display is in the right
half, on the top.
Once I compared the two
innards, I realized that their electronics were identical (as I had
hoped), except that the IVT-16 was simply missing an LCD
Even the connector where it would be plugged into was intact.
Inside view of the IVT-16, note the missing display although its
connector (orange) is present. The spacing of the pins on
the connector is 2mm (0.075"), and there are
When the IVT-16 is powered up, its 'MEM' LED lights up, perhaps as a
power indicator (since there is no display). When I unplugged
LCD panel from the IVT-16D, its 'MEM' LED lit up too! This
implies that the firmware on both phones is similar, except the
microprocessor detects the missing LCD, and lights the 'MEM' LED
up. I then plugged in the LCD panel from the IVT-16D phone
the IVT-16, and the display showed text! This confirms that
firmware is functionally the same on both phones.
A closer look at the LCD panel on the IVT-16D shows that it has a
'44780' microprocessor. I was really happy to see that
as many LCD panels that are available on the surplus market use this
controller. I thought to myself, perhaps I could simply
an LCD panel and upgrade
my IVT-16? A look at my favorite surplus place
showed that they had a 20x2 display (model
approximately the correct overall size. It's price was $6.50.
I purchased two LCD displays (one spare), and found a 2mm connector to
the phone board. I then connected the display to the orange
connector on the phone board (pin 1 to pin 1, etc). When I
plugged the phone into the phone
system. Success! The display lit up.
mounting holes in the panel lined up with the screw holes in the phone
case. I then attached the display into
the phone with some screws and covered the opening with a clear sheet
The new display inside the IVT-16. I used a 30 pin
hold the 14 wires so that
it could be plugged into the back of the LCD display.
The finished installation of the display. The whole opening
covered with a clear plastic sheet cut to the correct dimensions.
It is nearly impossible to see
clear plastic in
Incidentally, I also purchased a 24x2 LCD display from All Electronics
already had a 2 mm connector on it, I
plugged it into the phone, and that worked also. However, the
extra width prevented a good way of mounting the display into the
phone. I presume the extra eight characters on the display
remain blank. This compatibility does not surprise me as the
44780 controller is addressed the same way regardless of the size of
So to summarize, the overall upgrade project cost is about $7.00 (with
shipping, etc), and one 2 mm connector from my junk pile. On
the IVT-16 costs $135, while the IVT-16D costs $165, so I saved myself
a little bit of money. As we can see, it is easily performed
using commonly available components.
the internal lithium battery
The configuration of the system, and the system time (but not the
outgoing auto-attendant message) is stored on a M48T08-150
Lithium battery backed RAM
At around 2012, the system no longer preserved its
after power cycles, and it was clear that the battery was depleted
after 15 years of operation. Not bad really. I
install an external battery holder to solve this problem completely.
I opened the system and found the RAM module (it is socketed and on the
main board), I did a web search and
from someone that actually ground open the module to
install an external battery.
Photo of the RAM module ground open to expose the small Lithium battery.
Note that the side opposite from the case's pin 1 is ground open.
above photo shows the RAM module ground open with my bench top grinder.
The bottom case of the battery is the '+' terminal, and it is
welded to the contact circled in red. While the top terminal
connected to the one circled in blue (but interrupted here).
found that once I ground through the case, the potting material
(slightly grey) was softer, and I could pick it away with a sharp
RAM module with external battery.
wired a long pair of wires to the terminals and attached to CR2032
batteries. Instead of storing the new batteries inside the
(which would give a cleaner look), I decided to have the batteries be
external so that I would not have to disconnect the phone wires the
Tips and Tricks
There is a serial port
on the system
unit that connects to a PC for
programming. In my case, the PC is far from the system unit, so I
to run some kind of cable. It turns out that only three of the nine
on the DB9 are used (2,3, and 5), so I plugged in a DB9-RJ11 adapter.
to use a regular phone line to connect the system unit to the PC. This
arrangement actually looks very good since the whole interface to the
unit is power and RJ11 plugs.
- May 1997 - Installation
of the main
- July 1997- There has
been a complete
cessation of those annoying
calls! The auto attendant message is able to make it clear that they
- November 2001 - Added door phone from
- October 2003 -
Purchased a spare
IPS416 unit (with the highly
desired Caller-ID option) for $127 on ebay. A real good
deal compared to the price I paid for the original unit ($900,
ouch). The spare unit will be used if the original is damaged
to lightning or other major surge. These units are in
surprisingly high demand on ebay, and I had to wait for several months
before I was fortunate enough to purchase one at this price.
Label on the back of the second unit from ebay. The "CID" on
(and a label on the CPU) confirms it has the
If the unit does not have Caller-ID, the CID will be "MVX" (example
- November 2003 - Purchased two IVT-16D alpha-numeric
$42 each on ebay (these phones normally auction for at least
who has the best on-line price for these phones sells them for about
- February 2004 - Purchased an IVT-16N phone (no LCD display)
ebay for $36 (+ shipping), and added a display (see above).
have 6 key phones with alpha-numeric
2 without. Specifications on the display:
- Optrex #DMC-50218.
- Viewing area, 3.26" x 0.7".
- Module size, 4.58" x 1.46".
- 5 x 8 dot
- Prepped with 7 x 2 dual-row header, 0.1" spacing.
- October 14, 2004 - Purchased an IVT-16N (no LCD display) on
$28 (+9 shipping). Display added as above.
- October 15, 2004 - Purchased an IVT-16D on ebay for $0.01
shipping). What a great buy.
- October 23, 2004 - Purchased an IVT-16D on ebay for $1.57
shipping). Now I have plenty of spares.
- December 5, 2006 - Purchased two IVT-16D on ebay for $41
- November 13, 2007 - Problem with door phone unit.
stopped working. When I connect to the door unit from an
phone, I get a fast busy signal. After an investigation, I
that the problem is a simple wire break to the door unit.
the main box reacts by sounding a fast busy in this case. I
recall that when I purchased the unit, they sent me a custom chip that
makes it compatible with phone systems. The fast busy does
occur with the original controller chip. The manufacturer is
and I contacted them to purchase a spare controller chip (Model #N8-NC)
- September 1, 2014 - Added external
lithium battery for the battery backed RAM.
2015 - After 18 years of service, BBS unit #1 experienced a
failure. When a non-system phone is called, the system
reset. It appears that sending the high voltage ring signal
causes the reset of the system. This reset is similar to a
cycle. I replaced it with a spare unit (#2). #1
repaired in the future.
2016 - Replacement of Door Fon parts. I had picked up spares
low cost on Ebay over the years, and these came in handy. The
outside unit button, mike and speaker had degraded (seamingly all
together) so those were replaced. Also, the inside controller
not consistently detect that someone wanted to connect to the door
(from inside the house). This original set was in use almost
- March 2020 - Received email from Paul regarding the repair of his unit.
repaired my IPS416-CID. I put an oscilloscope on the power supply's 5V
output and saw a lot of ripple, even when not ringing. Rather than
troubleshoot further, I simply replaced all seven of the power supply
section's electrolytic capacitors (C25-C31) and that fixed it.
are very versatile phone systems! I've never found anything else with
quite the same functionality at a similar price point or footprint, so
I also have a spare unit. This isn't the first repair I've done on
them. If you get your phone service from a traditional landline
provider and have ever lost a trunk port to a surge, the part that
usually fails is its LCA110 6-pin DIP solid-state relay on the
daughter-board. When I've replaced them I added a 6-pin DIP socket to
make future replacement easier.
Corner of BBS unit with power supply. Meter reference is D3 in black box
result above is one that I should have foreseen. Problems during
high draw events that lead to reset strongly suggest a power supply
issue. So kudos to Paul for thinking of this. I opened up
my 'bad' unit to get some additional info, and found that the unit has
a positive voltage supply and a fairly high voltage negative supply.
The latter is probably for the 'ring' power. Anyone
repairing these supplies should check the ripple of these during high
current draw events or just replace the power capacitors as Paul
(under the big white resistor), 5V is C19 in the red box (left),
+11V raw supply is yellow box, -43V raw supply is pink box.
- August 2022 - I performed a repair on the failed unit from
(BBS #1). The ripple on the six capacitors in the bottom-right of
the above image were all about 50mVrms except for C27. This
1000uF capacitor measured 800uF and had 0.8Vrms of ripple. I
replaced this unit and the ripple was reduced to 0.2Vrms. The
unit no longer resets when a non-key phone is called. I also used
this opportunity to delid and attach a remote battery holder to the
RAM. The battery holder was from a toy LED bracelet and uses a
CR2032 battery (shown below).
- I did some research on backup power for the key
is a bit annoying to walk all over the house to enable "Auto-Answer"
when power is cycled on the system unit. The phones are powered
by about 30-34Vdc on the outer pair of wires on the modular phone cable
(yellow-black pair). A voltage as low as 5V will keep the
settings on the phones. It turns out that the 16 phones are
powered in four banks. So it is not possible to have a common
feed to provide them with standby power.
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