Videx VANDAL RESISTANT User manual

TECHNICAL MANUAL
EDITION 1.1
VANDAL RESISTANT
AUDIO AND VIDEO
DOOR ENTRY SYSTEMS

PAGE 2 of 24 AUDIO/VIDEO VANDAL RESISTANT TECHNICAL MANUAL VER1.1

PAGE 3 of 24 AUDIO/VIDEO VANDAL RESISTANT TECHNICAL MANUAL VER1.1
CONTENTS
PAGE
Manual introduction 4
System introduction 4
System components 4 – 11
Vandal resistant panel layouts 5
Accessories 12
Installation 12 – 14
Cable size guide 13 – 14
Audio system block diagram 14
Video system block diagram 15
Testing the installation 15
Panel care 15
Accessories connection guide 16
Single entrance single button audio wiring diagram 17
Single entrance multiple button audio wiring diagram 18
Two entrance audio wiring diagram 19
Single entrance video system wiring diagram 20
Two entrance video system wiring diagram 21
Audio system trouble shooting guide 22
Video system trouble shooting guide 23

PAGE 4 of 24 AUDIO/VIDEO VANDAL RESISTANT TECHNICAL MANUAL VER1.1
MANUAL INTRODUCTION
The information in this manual is intended as an installation and commissioning guide for
the standard range of vandal resistant door panels, to be used with standard AC buzzer
telephones or with vandal resistant video panels using the Art.890 controller. This manual
should be read carefully before the installation commences. Any damage caused to the
equipment due to faulty installations where the information in this manual has not been
followed is not the responsibility of Videx Security Ltd.
VIDEX run free training courses for engineers who have not installed this system before.
Technical help is also available on 0191 224 3174 during office hours or via e-mail
[email protected].
SYSTEM INTRODUCTION
This system can be used for single entrances or multiple entrances. The system has no
limit on the number of apartments for which it can control or the number of entrance points
that can be connected together, although we suggest using this system on small to
medium sized installation of no more than 20 apartments and three entrances.
SYSTEM COMPONENTS
A standard audio system will comprise of a door panel, power supply and audio
telephones. A standard video system will comprise of a door panel, video controller, power
supply, video splitters and videophones. The individual parts are described below.
DOOR PANELS
A vandal resistant door panel will consist of an amplifier module, button connector board
and ‘n’ number of buttons.
Speech volume adjustments are carried out at the door panel using a small trimmer driver.
Connection Function Connection Function
1 Receive speech from apartment LOCK Spare connector terminals
2 Transmit speech to apartment CB Common of call buttons
3 +12Vdc input A Spare connection terminal
4 0V (Ground) 1 Call button 1 connection
2 Call button 2 connection
3 Call button 3 connection
4 Call button 4 connection
Camera module (Art.830 & 830C) 5 Call button 5 connection
Connection Function
6 Call button 6 connection
I +20Vdc input 200mA (400mA - 830C) 7 Call button 7 connection
F1 0V 8 Call button 8 connection
V Centre core of coax video cable 9 Call button 9 connection
M Screen of coax video cable 10 Call button 10 connection
SB +8-12Vdc camera heater TRADE Trade button connections
Adjustment for
speech volume level
at the door station
Adjustment for
speech volume at the
apartment
Amplifier module (Art.437 or Art.537) Connector PCB (CB)

PAGE 5 of 24 AUDIO/VIDEO VANDAL RESISTANT TECHNICAL MANUAL VER1.1
VANDAL RESISTANT PANEL LAYOUT AND SIZES
Standard audio panels
Other standard panel sizes:-
1 – 10 button with video [180mm (W) x 256mm (H) x 50mm (D)]
11 – 20 button + video [200mm (W) x 350mm (H) x 50mm (D)]
1 – 10 button + proximity [180mm (W) x 256mm (H) x 50mm (D)]
11 – 20 button + proximity [200mm (W) x 350mm (H) x 50mm (D)]
1 – 10 button + codelock [180mm (W) x 256mm (H) x 50mm (D)]
11 – 20 button + codelock [200mm (W) x 420mm (H) x 50mm (D)]
1 – 10 button + video & proximity [200mm (W) x 350mm (H) x 50mm (D)]
1 – 10 button + video & codelock [200mm (W) x 420mm (H) x 50mm (D)]
1 BUTTON = C
2 BUTTON = B, D (Note: Also available in 125mm 220mm panel style)
3 BUTTON = A, C, E
4 BUTTON = B, D, G, I
5 BUTTON = A, C, E, G, I
6 BUTTON = A, C, E, F, H, J
7 BUTTON = A, B, C, D, E, G, I
8 BUTTON = A, B, C, D, E, G, H, I
9 BUTTON = A, B, C, D, E, F, G, I, J
10 BUTTON = A, B, C, D, E, F, G, H, I, J
11 BUTTON = A, C, E, F, H, J, K, M, O, Q, S
12 BUTTON = A, C, E, F, H, J, K, M, O, P, R, T
13 BUTTON = A, C, E, F, H, J, K, M, O, P, Q, S, T
14 BUTTON = A, C, E, F, H, J, K, M, O, P, Q, R, S, T
15 BUTTON = A, B, C, D, E, F, G, H, I, J, K, L, M, N, O
16 BUTTON = A, B, C, D, E, F, G, H, I, J, K, L, M, N, O, R
17 BUTTON = A, B, C, D, E, F, G, H, I, J, K, L, M, N, O, Q, S
18 BUTTON = A, B, C, D, E, F, G, H, I, J, K, L, M, N, O, P, R, T
19 BUTTON = A, B, C, D, E, F, G, H, I, J, K, L, M, N, O, P, Q, S, T
20 BUTTON = A, B, C, D, E, F, G, H, I, J, K, L, M, N, O, P, Q, R, S, T

PAGE 6 of 24 AUDIO/VIDEO VANDAL RESISTANT TECHNICAL MANUAL VER1.1
AUDIO SYSTEM POWER SUPPLY
Art.520M
The standard power supply is the Art.520M. Outputs of 12Vdc (200mA), 8Vdc (300mA)
and 13Vac (1A) are available. The dc outputs are designed to power the amplifier modules
only and can not be used to power other devices such as code locks, lock releases etc.
These items must be connected to the AC output of this power supply.
VIDEO SYSTEM POWER SUPPLY AND CONTROL UNIT
Art.890
The 890 control unit is used on video systems. Its functions include call tone generation,
voltage regulation and switching to both door panels and videophones, lock release control
and camera recall. The Art.890 requires both 13Vac and 24Vac to operate.
.
CONNECTIONS
CONNECTIONS
Terminal Function
+12 12Vdc output (200mA Max.)
+8 8Vdc output (300mA Max.)
- 0V (Ground)
~ 13Vac (1A Max.)
230 Mains in (Live connection)
0 Mains in (Neutral connection)
Terminal Function
~ & ~ Power input 24Vac
~& ~ Power input 13Vac
1 Switched 20Vdc to videophones (Only on during a call)
2 Switched negative from videophones to activate lock
3 Receive speech from videophone
4 Transmit speech to videophone
5 Ground for speech circuits
6 Ground for video circuits
TV1 Camera recall facility
T Electronic call tone output for call buttons
A 13Vac output for ac lock release
+8 8Vdc output 200mA max.
F Ground for door panel speech circuits
E Push button commons for AC calling
I Switched 20Vdc for camera (Only on during a call)
G2 Receive speech from door panel
H1 Transmit speech to door panel
F1 Negative supply for camera unit
F2 Switched negative (Switches off when lock released)
SE Switched negative to lock
+12V 12Vdc output 200mA max.
V & M Coax in from camera (V=Centre core, M=Screen)
V & M Coax out to videophones (V=centre core, M=Screen)
For more information
on the Art.890 please
see the Videx Video
technical manual
Fuse
compartment

PAGE 7 of 24 AUDIO/VIDEO VANDAL RESISTANT TECHNICAL MANUAL VER1.1
Art.850
The 850 transformer includes a 13Vac (1A max.) output and a 24Vac (1A max.) output.
Each of the two outputs is individually fused.
CONNECTIONS
Art. 893N
Art.701
20Vdc 800mA continuous 1A surge PSU and is used as a booster
supply or when more than two videophones are required in an
apartment. This power supply only has an output when either a 0V
is applied to –C or when a voltage is applied to +C. At all other
times the + output is switched off.
Connection Function
230V~ 0 Mains voltage input
+ Switched 20Vdc output (Triggered by –C or +C)
- 0V
-C 0V trigger input (From 4V to 0V)
+C + volts trigger input (From 8V up to 30V)
D+ Switched +20Vdc output via diode
BST/GMT digital time clock. This time clock operates from a 12Vac
or dc power supply. The output is a dry contact relay. When used
with this system the trade button input is used. This allows the dry
contact relay to drive the lock release directly. The relay can be
programmed to release the lock for 1 – 99 seconds.
Connection Function
+ 12Vac or dc voltage input
- 0V
TR Trade button input (Switched 0V)
C Common connection on relay
NO Normally open connection on relay
NC Normally closed connection on relay
For more information see time clock instruction sheet
Terminal Function
24V 24V ac output
13V 13V ac output
230V Live mains connection In
0 Neutral mains connection In
Fuse
compartment

PAGE 8 of 24 AUDIO/VIDEO VANDAL RESISTANT TECHNICAL MANUAL VER1.1
CONNECTIONS
Connection Function
- 0V connection from PSU
~ 13Vac supply input
A1 Current sensing path for call
A2 from door A
B1 Current sensing path for call
B2 from door B
1 Receive speech from telephone
2 Transmit speech to telephone
5 Lock trigger from telephone
1A Transmit speech to door A
1B Transmit speech to door B
2B Receive speech from door A
2B Receive speech from door B
5A Lock trigger to door A
5B Lock trigger to door B
LA LED command (Speech open to door A)
LB LED command (Speech open to door B)
R Reset signal (To other Art.502’s)
CONNECTIONS
Connection Function
1 13Vac supply input
2 0V connection
3 Current sensing path for call
4 from door A
5 Current sensing path for call
6 from door B
R Reset signal (To reset other Art.892’s)
7 Receive speech from videophone
8 Transmit speech to videophone
9 Lock release command from Art.890
10 Centre core of coax to apartments
11 Screen of coax to apartments
12 Switched 20Vdc from Art.890
7A Transmit speech to door A
7B Transmit speech to door B
8A Receive speech from door A
8B Receive speech from door B
9A Lock trigger to door A
9B Lock trigger to door B
10A Centre core of coax from door A camera
10B Centre core of coax from door B camera
11A Screen of coax from door A camera
11B Screen of coax from door B camera
12A 20Vdc to power camera at door A
12B 20Vdc to power camera at door B
Art.502
The Art.502 is a two door
switching relay for an audio
system. One unit is required for a
two door system, one unit per door
is required for a three or more door
system. The Art.502 switches both
audio and lock release request to
the door that calls. The relay stays
latches at the last door called.
Art.892
The Art.892 is a two door
switching relay for a video system.
One unit is required for a two door
system, one unit per door is
required for a three or more door
system. The Art.892 switches
audio, video and lock release
request to the door that calls. The
relay stays latches at the last door
called.

PAGE 9 of 24 AUDIO/VIDEO VANDAL RESISTANT TECHNICAL MANUAL VER1.1
AUDIO TELEPHONES
Art.3101
Art.3021
Art.3102
The Art.3101 AC buzzer phone includes a lock release push button
and spare dry contact push to make button for other services.
Smart line AC buzzer phone includes a lock release
push button.
CONNECTIONS:-
Function
1 Transmit speech to the door panel
2 Receive speech from the door panel
3 0V
4 Not used (Electronic call tone input)
5 Lock trigger (Switched 0V)
6 Call line (13Vac input to trigger buzzer)
8 Dry contact switch
9
The Art.3102 AC buzzer telephone includes a lock release push
button and spare dry contact push to make button for other services.
Additionally it includes a slide mute switch to turn the phone off when
the tenant does not want to be disturbed.
CONNECTIONS:-
Function
1 Transmit speech to the door panel
2 Receive speech from the door panel
3 0V
4 Not used
5 Lock Trigger (Switched 0V)
6 Call line (13Vac input to trigger buzzer)
8 Dry contact switch
9
5
5

PAGE 10 of 24 AUDIO/VIDEO VANDAL RESISTANT TECHNICAL MANUAL VER1.1
VIDEOPHONES
Art.3312
DIP SWITCH SETTINGS
The Art.3312 (3412 for colour) includes a lock release push
button, camera recall button and three dry contact push to
make spare push buttons for other services. Coax and non-
caox video can be used by setting the relevant dip-
switches. An Art.3980 back plate is required with this
videophone.
CONNECTIONS:-
Function
1 +12V out to power video splitter
2 Camera recall
3 Spare button
4 +20V power input
5 Door release command
6 Transmit speech to door panel
7 Receive speech from door panel
8 Speech Ground
9 Video power ground
10 Local call tone input
11 Coax centre core
12 Coax Screen
13 Speech common for intercommunicating systems
14 Call tone input
15 Speech ground for intercommunicating systems
16 Common of spare buttons
17 Spare button
18 Spare button
9 + Coax
Or
11 cores

PAGE 11 of 24 AUDIO/VIDEO VANDAL RESISTANT TECHNICAL MANUAL VER1.1
Art.3313
The Art.3313 (3413 for colour) includes a lock release push button and two dry contact push
to make spare push buttons for other services. An Art.3980 back plate is required with this
videophone.
CONNECTIONS:-
Function
1 +12V out to power video splitter
2 Not used
3 Spare button
4 +20V power input
5 Door release command
6 Transmit speech to door panel
7 Receive speech from door panel
8 0V (Ground)
9 Not used
10 Local call tone input
11 Coax centre core or non-coax sync-
12 Coax Screen or non-coax Sync+
13 Switched +12 for door open LED
14 Select input to switch on videophone
15 Call tone input
16 Common of spare buttons
17 Spare button
18 +12V to power videophone privacy
DIP SWITCH SETTINGS
8 Way dip switch (Switches 1 – 5)
Mute Duration time
Time 1 2 3 4 5
15 Minutes ON OFF OFF OFF OFF
30 Minutes OFF ON OFF OFF OFF
2 Hours OFF OFF ON OFF OFF
4 Hours OFF OFF OFF ON OFF
8 Hours OFF OFF OFF OFF ON
3 Way Dip Switch
VIDEO MODE continued
Switch 1 2 3
Coax OFF OFF OFF
Non-Coax ON ON ON
8 Way dip switch (Switch 6)
Mute LED
Switch 6
Fixed OFF
Flashing ON
8 Way dip switch (Switches 7 & 8)
°° Button Operation
Switch 7 8
Camera recall ON OFF
Dry contact OFF ON
4 Way Dip Switch (Switches 1 & 2)
S Button Operation
Switch 1 2
Camera recall ON OFF
Dry contact OFF ON
4 Way Dip Switch (Switches 3 & 4)
VIDEO MODE
Switch 3 4
Coax ON ON
Non-Coax OFF OFF

PAGE 12 of 24 AUDIO/VIDEO VANDAL RESISTANT TECHNICAL MANUAL VER1.1
ACCESSORIES
Art. 512A, Art.512R
ES/1
INSTALLATION
The wiring diagrams towards the back of this manual should be followed carefully. Heavy
duty conductors on wiring diagrams are shown heavily outlined, These wires should be
doubled up.
- Check that all components are free from damage before installing (Do not proceed with
installation in the event of damage).
- Keep all packaging away from children.
- Do not obstruct the ventilation openings or slots on any of the devices.
- All connections to mains voltages must be made to the current national standards (IEE
Wiring regulations)
- Install an appropriate fused spur or isolation switch to isolate the mains.
- Isolate the mains before carrying out any maintenance work on the system.
- All intercom and access control cables must be routed separately from the mains.
Extension sounder for an apartment. This sounder can be wall
mounted and will ring whenever the telephone it is connected to
rings. The 512A is used on video systems and the 512R is used on
A
C buzzer audio s
y
stems
Timed strobe unit for the hard of hearing or noisy environments.
The strobe will flash when a call is received and will continue
flashing for an adjustable time period or until the reset button is
pressed.
512A Connections
4 Call tone input
- 0V (Ground)
Connections
POWER 12V AC or DC input
I/P + trigger
+O/P 12Vdc output
GND Ground
RESET Switched negative reset
NC Normally closed relay connection
CO Common relay connection
NO Normally open relay connection
The 512R has two non-polarity
connections requiring 13Vac to
buzz

PAGE 13 of 24 AUDIO/VIDEO VANDAL RESISTANT TECHNICAL MANUAL VER1.1
Lock release back EMF protection : A capacitor must be fitted across the terminals on
an AC lock release and a diode must be fitted across the terminals on a DC lock release
as shown in the diagrams below to suppress back EMF voltages.
LOCK RELEASE
12V AC
~~ 0.1uF capacitor
+
-1N4002 +
-
12V DC
LOCK RELEASE
DIODE
CABLE SIZE GUIDE
AUDIO SYSTEM
Connections from door panel to telephone.
Connections 50m 100m 200m 300m 400m
1 0.25mm² 0.35mm² 0.5mm² 0.75mm² 1.0mm²
2 0.25mm² 0.35mm² 0.5mm² 0.75mm² 1.0mm²
3 0.5mm² 0.75mm² 1.5mm² 2.0mm² 2.5mm²
5 0.5mm² 0.75mm² 1.5mm² 2.0mm² 2.5mm²
6 0.25mm² 0.35mm² 0.5mm² 0.75mm² 1.0mm²
When ever possible connection 1(Tx) should be twisted with connection 3(Gnd) and connection 2(Rx) should
be twisted with connection 3(Gnd) as pairs.
Maximum acceptable resistance for terminals 1,2 & 6 = 10Ωand for terminals 3 & 5 = 3Ω
Connections for power supply output to door panel and lock release connections.
50m 100m
Connections 0.5mm² 0.75mm²
The power supply should be located as close to the door panel as possible for best performance.
Maximum acceptable resistance for above cables = 3Ω
VIDEO SYSTEM
Connections from door panel to the Art.890 controller.
Connections 50m 100m 200m 300m 400m
T 0.35mm² 0.5mm² 0.5mm² 0.75mm² 1.0mm²
A 0.5mm² 1.0mm² 1.5mm² 2.0mm² 2.5mm²
+8 0.35mm² 0.5mm² 0.75mm² 1.0mm² 1.5mm²
F 0.35mm² 0.5mm² 0.75mm² 1.0mm² 1.5mm²
I 0.35mm² 0.5mm² 1.0mm² 1.5mm² 2.0mm²
G2 0.35mm² 0.35mm² 0.5mm² 0.75mm² 1.0mm²
H1 0.35mm² 0.5mm² 0.75mm² 1.0mm² 1.5mm²
F1 0.35mm² 0.5mm² 0.75mm² 1.0mm² 1.5mm²
F2 0.35mm² 0.5mm² 0.75mm² 1.0mm² 1.5mm²
SE 0.5mm² 1.0mm² 1.5mm² 2.0mm² 2.5mm²
V Standard quality Medium quality Good quality Good quality High quality
M 75ΩCoax cable 75ΩCoax cable 75ΩCoax cable 75ΩCoax
cable
75ΩCoax
cable
When ever possible connection H1(Tx) should be twisted with connection F(Gnd) and connection G2(Rx)
should be twisted with connection F(Gnd) as pairs.

PAGE 14 of 24 AUDIO/VIDEO VANDAL RESISTANT TECHNICAL MANUAL VER1.1
Maximum acceptable resistance for terminals T, G2, H1 = 10Ωand for terminals A, +8, F, F1 & I = 6Ωand
for terminals SE & F2 = 3Ω
V is the centre core of the coax and M is the screen.
The transformer should be mounted next to the Art.890 and connected using 1mm² cores
Connections from the Art.890 controller to the videophone.
Connections
Numbers in brackets are
those of the videophone
back plate. Without
brackets are signal
50m 100m 200m 300m 400m
+12(1) 0.35mm² 0.35mm² 0.5mm² 0.75mm² 1.0mm²
TV1(2) 0.35mm² 0.35mm² 0.5mm² 0.75mm² 1.0mm²
TV2(3) 0.35mm² 0.35mm² 0.5mm² 0.75mm² 1.0mm²
1(4) 0.35mm² 0.5mm² 1.0mm² 1.5mm² 2.0mm²
2(5) 0.35mm² 0.35mm² 0.5mm² 0.75mm² 1.0mm²
3(6) 0.35mm² 0.35mm² 0.5mm² 0.75mm² 1.0mm²
4(7) 0.35mm² 0.35mm² 0.5mm² 0.75mm² 1.0mm²
5(8) 0.35mm² 0.35mm² 0.5mm² 0.75mm² 1.0mm²
6(9) 0.35mm² 0.5mm² 1.0mm² 1.5mm² 2.0mm²
7(10) 0.35mm² 0.35mm² 0.5mm² 0.75mm² 1.0mm²
V(11) Standard quality Medium quality Good quality Good quality High quality
M(12) 75ΩCoax cable 75ΩCoax cable 75ΩCoax cable 75ΩCoax
cable
75ΩCoax
cable
R(13) 0.35mm² 0.35mm² 0.5mm² 0.75mm² 1.0mm²
C(14) 0.35mm² 0.35mm² 0.5mm² 0.75mm² 1.0mm²
-(15) 0.35mm² 0.35mm² 0.5mm² 0.75mm² 1.0mm²
T(16) 0.35mm² 0.35mm² 0.5mm² 0.75mm² 1.0mm²
1T(17) 0.35mm² 0.35mm² 0.5mm² 0.75mm² 1.0mm²
2T(18) 0.35mm² 0.35mm² 0.5mm² 0.75mm² 1.0mm²
When ever possible connection 3(6) should be twisted with connection 5(8) and connection 4(7) should be
twisted with connection 5(8) as pairs.
Maximum acceptable resistance for all terminals except 1(4) & 6(9) = 10Ωand terminals 1(4) & 6(9) = 6Ω
V is the centre core of the coax and M is the screen.
AUDIO SYSTEM BLOCK DIAGRAM
Note: Additional cores will be required for auxiliary devices such as push to exit buttons,
fireman switches, proximity access control etc.
Art.3021, 3101, 3102
5
5
5

PAGE 15 of 24 AUDIO/VIDEO VANDAL RESISTANT TECHNICAL MANUAL VER1.1
VIDEO SYSTEM BLOCK DIAGRAM
Note: Additional cores may be required for auxiliary items such as push to exit buttons,
fireman switch proximity access control etc..
The block diagram above shows all videophones coming back to one point with all the
video distributors at that point. It is also possible to spread the video distributors around
the building (Please see wiring diagrams for more information).
Safety Note : An earth connection should also be fitted to the door panel stainless steel
facia using one of the studs provided.
TESTING THE INSTALLATION
- Check all the connections have been made correctly and then power up the system.
- Call all the apartments in turn. Check for call tone to the apartment, speech in both
directions, video (optional) and lock release.
- If the volume of speech needs to be adjusted, this can be done by adjusting the presets
on the rear of the amplifier at the door panel.
- On calltone call system only, if the call tone volume needs adjusting this can be done at
each handset (Three position slid switch on the telephone).
- Set the time clock on/off times (Use the instructions supplied with the time clock).
Check the trade button only works when the time clock is on.
PANEL CARE
The door panels are manufactured from either 12 Gauge 304 grade stainless steel or
mirror finished brass. It is important that the facia is cleaned on regular occasions to
prevent dirt build up and tarnishing of the metal. A general household metal polish can be
used but care should be taken to follow the grain of the metal when polishing and also
avoid any polish build up around the call buttons which may prevent the buttons from
operating correctly.

PAGE 16 of 24 AUDIO/VIDEO VANDAL RESISTANT TECHNICAL MANUAL VER1.1
ACCESSORIES CONNECTION GUIDE
3101
3101
3101

PAGE 17 of 24 AUDIO/VIDEO VANDAL RESISTANT TECHNICAL MANUAL VER1.1
WIRING DIAGRAM
This diagram shows a single
entrance vandal resistant door
panel connected to two audio
phones in the same apartment.
The lock release shown is fail
secure 12Vac.

PAGE 18 of 24 AUDIO/VIDEO VANDAL RESISTANT TECHNICAL MANUAL VER1.1
WIRING DIAGRAM
This diagram shows a single entrance
vandal resistant door panel connected to
multiple apartments. The lock release
shown is fail secure 12Vac. We suggest
running all telephones back to one point
(i.e. junction box next to power supply unit)

PAGE 19 of 24 AUDIO/VIDEO VANDAL RESISTANT TECHNICAL MANUAL VER1.1
WIRING DIAGRAM
This diagram shows a two entrance
multiple apartments system. 12Vac fail
secure lock releases.

PAGE 20 of 24 AUDIO/VIDEO VANDAL RESISTANT TECHNICAL MANUAL VER1.1
WIRING DIAGRAM
This diagram shows a single
entrance VR video door panel
connected to a single apartment with
two videophones.