BT HAWK (CORDLESS TELEPHONE)
|Introduced in 1983 the HAWK
(illustrated opposite) is British Telecom's first cordless telephone. Available in ivory
and brown it consists of 2 parts,
a. A free standing or wall mounted BASE UNIT which is connected to the telephone line using Phone Socket, and......
b. A portable HANDSET that can be carried around the customers premises and will give the user the same facilities as a conventional telephone. When not in use the handset is placed upon the base unit for recharging.
Speech and signalling is transmitted between the handset and base unit using 2 low-power radio links, with a range under ideal conditions of up to 100 metres. Walls and other large obstructions, particularly metal, will reduce the usable range.
Because only 8 pairs of radio channels have been provided for the whole of the UK, then it is possible that HAWK customers living near to each other and using the same radio channels may experience overhearing or other operational difficulties. This is unavoidable, but since the range of the telephone is only 100 metres it is envisaged that this will only happen occasionally.
Although difficulties may be experienced, there is only a slight chance that two adjacent customers will be able to make calls on each others line, even though they may use the same radio channels. This is because during manufacture, a security code is allocated to each base unit and handset so that they become a matched pair. Whenever calls are made or received, the security code is exchanged between them, and the call only allowed to mature if the exchange of code is correct.
Because of the security code arrangements it is not possible to use the handset with other than the base unit supplied.
When received, the Hawk handset will require charging for approx. 24 hours before it is installed, otherwise it will not be possible to test it on site. Read through this guide note fully before attempting to charge the handset. After charging, repack Hawk carefully for transportation to the customers premises.
The main features of the base unit are:-
The main features of the handset are:
The LINE INTERFACE electrically isolates the telephone line from the rest of the base unit circuitry, and performs the electrical functions of a normal telephone, i.e. impedance matching, regulation, ringing detection, dialling (by relay) and speech transfer to and from the line.
The CONTROL CIRCUIT utilises information from the receiver and line interface to control the transmitter and access to line. A microprocessor and a read only memory (ROM) programmed with the security code are used in this control. Elements of the microprocessor are also used to shape the dialling pulses from the handset.
The 1.7MHz TRANSMITTER develops some 500mW of power. The electromagnetic field near to the output coil which is connected to the transmitters wire aerial, is sensed and then amplified to drive the 'in use' lamp. Maximum brightness of the lamp indicates that the aerial is correctly aligned.
Like the base unit, the CONTROL circuitry uses a microprocessor and associated Read Only Memory to send and receive the security code and also to generate the calling tones for the earpiece. The control circuit takes the number information from the keypad and arranged for the 4.5kHz sub carrier to be pulsed at the required rate.
The 1.7MHz RECEIVER utilises a ferrite rod aerial similar to those found in medium /long wave broadcast receivers.
Installation of base unit
1. Telephone Connexion
Plug the telephone line cord, from the base unit, into the BT phone socket.
2. Power Supply
Put the small plug on the power cable into the socket marked "POWER" on the back of the base unit. Insert the plug-mounted transformer into the mains power supply and switch on. The "POWER" light will glow.
The base unit has two aerials, one telescopic and the other an aerial wire.
Extend the telescopic aerial on the base unit, and arrangevertically.
Extend the aerial wire to its full length.Remove the handset from the base and put to one side. Depress the "CALL" button on the base unit. This will make the green "IN USE" lamp glow. Changing the position of the aerial wire will cause the brightness of the lamp to vary. The aerial is in the ideal position when the glow is brightest; it should be fixed in this position. A vertical position should prove to be best.
(The aerials are finely tuned and should not be altered orchanged in any way. Any alteration will reduce the performance of your Hawk).
The portable handset
The handset has a rechargeable battery which mayrequire charging for a maximum of 24 hours before use.
A fully charged battery will operate without recharging forup to 3 hours of continuous conversation or for 4-6 hours of intermittent use or for at least 24 hours on standby. It is charged by setting the handset to "STANDBY" and firmly placing it on the base unit so that the "CHARGE" light glows.
A full recharge- required when the "LOW BATTERY" light on the handset glows - will take a maximum of 24 hours.
It is recommended that the battery charge be kept toppedup by recharging at frequent intervals, particularly after long periods of use. You may find it convenient, for example, to charge overnight or while you are out of the house.
Charging may be interrupted to make or receive a call.
To make a call
2. Set the switch to "TALK". The lamp will glow.
3. When dial tone is received dial the number required.
4. At the end of the call, switch to "STANDBY". The "TALK" lamp will go out. Check that the call has been cleared by switching back to "TALK" and listening for dial tone. If dial tone is not heard move nearer to the base-unit and repeat unit dial tone is received, then switch back to "STANDBY".
Allow at least 3 seconds between calls.
To receive a call
2. An incoming call will make the handset ring. To answer, rotate the handset aerial to the vertical position and switch to "TALK". If the incoming speech is faint switch the on-off switch to "HI". If the volume is still too low move nearer to the base unit until speech is clearer.
3. At the end of the call switch back to "STANDBY".
Repeat last number
2. On receipt of this tone the portable handset user should proceed as in 'To receive a call'. The fixed telephone handset should be replaced in its cradle.
Last revised: February 24, 2021