The handset of the BT Response 510 is similar in design to the Relate range.

Response 510 is a combined telephone answering and recording machine with 13 minutes digital recording of messages. The announcement of the Response 510 is digitally recorded. In addition to usual Answerphone facilities, the Response 510 offers access to BT network services such as Call Waiting, Call diversion, reminder Call and Charge Advice. The Response 510 also allows message forwarding of recorded messages. Response 510 may be desk or wall mounted. The instrument has a LCD screen to display numbers dialled and provides a step through menu for programming the various functions.

The facilities of the instrument are as follows:-

Loudspeaking telephone allowing full handsfree operation.

Network Services:-
Four network service codes are pre-programmed into memory locations of the Response 510. These are;
Call waiting - memory 8 (recall 2)
Call diversion - memory 8B (*21*)
Charge advice - memory 9 (recall*40#)
Reminder call - memory 9B (*55*)

The line must have access to network services and the Response 510 must be set to T-TB. If it is not desired to use the pre-programmed network services codes, they may be over-written. The method is described in "- 20 memory stores" later in this document.

- Desk or Wall mounted.

- Mixed signalling. If set for LD signalling, pressing "*" will change signalling to MF4 until current call is cleared.

- Last number Redial. Up to 32 digits. A pause, recall, "*" or "#" counts as one digit.

- Latching Secrecy Button with LED indication.

- Dial Pause, 4 seconds.

- 20 Memory Stores. Up to 20 digits in length inclusive of pause, recall or 19#11.

Two numbers, known respectively as A or B, may be stored against each of the individual memory keys. To store the first number A; press STORE followed by the desired memory location, the display will show MEMORY A, key the required telephone number and end by pressing STORE. the display will flash the stored number for eight seconds.

To store the B number; press STORE followed by B MEMORY, the display will show MEMORY B. The procedure then becomes the same as above.

NB. Response 510 remains in store B for 12 seconds after entry. Subsequent entries into B stores may be made without pressing B memory provided they are made within the 12 seconds. After 12 seconds Response 510 reverts to A memory and the display changes to A.

 Day and time display and call timer.
To set the day; Whilst holding down the TIME key, press and hold the rewind key until the correct day is announced. Release the rewind key.

To set the hour; Whilst holding down the TIME key, press and hold the SAVE key until the correct hour is shown on the display. Release the SAVE key.

To set the minutes; Whilst holding down the TIME key, press and hold the >> key until the correct minute is shown on the display. Release the >> key.

- LCD display which displays digits dialled, monitors call progress and displays time. An Icon displays whether receiver is on or off hook.

- Digital announcement, up to 2 minutes in length. The LCD display counts down in seconds during recording demonstrating length of time remaining. To record the announcement; press and hold the ANN key, after a short delay a long beep will be heard and the display will show ANNOUNCEMENT RECORDING. Make the recording. The display will show the time remaining in seconds. When the recording is finished, release the ANN key. Response 510 automatically plays back your announcement and the display will show ANNOUNCEMENT PLAY. The display will change to PLAY for four seconds and then change to MESSAGES 00. Response 510 is now in answer mode.

The recording may be made via the Response 510 handset as an alternative to the in-built microphone and this will result in a slightly improved recording.

- Answer Only Announcement - Up to 2 minutes.

- Outgoing Announcement Check
To check the announcement press and release ANN. The announcement will be heard through the loudspeaker. Do not hold pressed the ANN key or Response 510 will begin to record a new announcement.

- Memo; Up to 30 seconds in length. Response 510 will indicate if a memo is recorded.
To record a memo; press and hold the MEMO key, the tape will rewind and a long beep will be heard. The display will show RECORDING and the memo indicator is lit. The memo may now be recorded, the display will count down the time remaining in seconds. When the memo is finished, release the MEMO key, a long beep will be heard and the MEMO indicator flashes to indicate that a memo has been left. The memo will be stamped with the current day and time.

- Built in microphone - Used for announcement and Memo recording.

- Play messages; If a message has been received The PLAY indicator will flash and the display will show the number of messages received.

To play messages; press PLAY, the display shows PLAY flashing. The Response 510 announces the number of messages stored followed by "please wait". The messages will then be played back through the loudspeaker or handset if desired for more privacy. At the end of each message the time and day of the recording is announced.

- Pausing messages; press PLAY. To continue playing messages, press PLAY again. The display shows PLAY.

- Message save; At the end of message play, Response 510 announces, "that was your last message". The display shows PLAY for a further four seconds, during this period pressing SAVE will save all messages. If SAVE is not pressed Response 510 will reset.
Providing the messages have not been over-written, pressing SAVE at any time will save all messages.
Messages accessed remotely will be saved automatically.

- Play all; Recovering unsaved messages.
If Response 510 has reset ie. messages have not been saved, they can be recovered by pressing PLAY. Response 510 will announce "You have no messages": Press PLAY again, Response 510 will announce "Please wait". The tape will rewind and play all messages that have not yet been overwritten.

- Fast forward/rewind during play;
Pressing rewind or>> during play will rewind or forward through messages. - Incoming Message up to 3 minutes.

- Skip Announcement - Frequent callers can key '*' from a Touchtone telephone or remote interrogator and leave a message without having to listen to the outgoing announcement.

- Volume Control - From minimum to maximum volume.

- Call Screening (Monitoring) - Listen to incoming callers leaving message. The volume control must be turned up to listen.

- Two way recording. A security tone is given every 15 seconds.

- Ring Adjuster; Default is 2 rings. Answering is programmable between 2 or 8 rings or TS. TS = time saver. In this mode, Response 510 will answer after 2 rings if messages have been left, or 6 rings if no messages have been left. This facility is useful when accessing remotely, if the Response 510 rings more than twice, the user can clear down knowing no messages have been left, thus saving the cost of a call.

To change see Menu.

- Remote set to Answer - Call machine and let it ring 20 times.

- Remote access; Customer programmable security code 0 to 9999 and OFF. Default = 510: to change see Menu

- Message Forwarding;
Message forwarding enables Response 510 to contact another telephone whenever a message is received. Response 510 will replay a message forwarding announcement when answered. If the receiver of the call enters the correct security code the message will be played.

For message forwarding to function, the facility must be on and the answer mode set to answer and record. The number for message forwarding must be stored in location 10A and a message forwarding announcement must be present.

The display will show FORWARD and MESSAGES.

Response 510 answers call
Response 510 records message
Response 510 dials message forwarding number
-YES-{Number answers) -NO-Response 510 times out and clears down two further attempts will be made 1 minute and three minutes later.

Response 510 plays message forwarding announcement
Security code entered
Response 510 plays message

If for any reason the called number does not wish to access the Response 510, keying a "*" will clear down the connection.

For setting the facility on and recording message forwarding announcement, see Menu.

- Remote access with a programmable security code.

Response 510 can be accessed remotely from a Touchtone telephone or by remote controller. The security code must be entered during announcement play. Most message facilities can be accessed remotely including setting the message forwarding on or off. The User Guide contains a comprehensive list of remote access functions.

- Program Menu

The menu allows changes to be made to the features of the Response 510. Facilities which can be accessed via the menu are;

Answer mode, toggle between answer and record or answer only.
Answer delay 2 to 8 or t.
Security code 0 - 9999 or off
Message forwarding announcement recording
Message forwarding on or off

To access press and hold PROGRAM, a beep will be heard and the display will show "Ann and rec". Further presses of the PROGRAM key will scroll through the menu. To alter the displayed feature use rewind or>> keys, press save to retain altered feature. Pressing ANSWER at the end of the menu or at any point in the menu, will exit from the menu.

To record the message forwarding announcement; step through by pressing PROGRAM until the display shows ANNOUNCEMENT FORWARD, press and hold ANN and wait for the beep. Begin recording, the display will show RECORD and will count down the time remaining (maximum 16 seconds). When the recording is completed, release ANN. Response 510 will automatically play the announcement., the display will show PLAY. If the message is satisfactory, press PROGRAM to advance through the features or ANSWER to exit the menu.

Made by Inventec Corporation.

Distributed by BT. Supplied on both Rental and Sale terms. Sold machines can be offered a BT maintenance agreement. BT UK Trade Sales, sale only.

Approval Number S/2981/3/P/502806

Approved for DEL and PBXs CAT 1, 3, 5 & 7.
Approved as supplied for connection to Public Switched Telephone Networks (PSTN) and 2-wire PBX extensions.

User Guide; TPU 1880 or 1880A supplied with the instrument.

The Response Combined Telephone and Answering Machine Product Manual PDM/TPM/A010

Customer Field Notes (CFN) containing transitory information and published as necessary.

A Phone Socket and a 240 volts, 13 amp, 50 Hertz mains supply socket are required within easy reach of the instrument. Transformer lead is 3.0 metres long and the line cord, 2.0 metres.

Suitable for use on Phone Socket installations on DELs and most types of 2-wire PBX extensions.

Ringer Equivalence Number (REN) is 1. See CFN 007 Telephones for further REN details.

The instrument does not contain any on-site serviceable parts. Therefore maintenance is limited to functional testing, checking the facility switches are set to provide optimum performance of the instrument to match the line to which it is connected, the condition of the tape and that the tape head is clean.
If the machine fails completely, the output voltage of the Transformer should be checked. The Transformer output is marked 9.5 volts dc, but will measure about 13 volts when tested with the output open circuit.

The customer should replace the 3 x AAA cells when the Batt Low symbol is displayed on the LCD.

Response 510 may be accessed remotely from any Touchtone telephone or by the use of a remote controller.

Accessing messages: Call the Response 510 and wait until it answers the call. During or after the announcement, operate the # key on the telephone or controller. Two beeps will be heard. From the keypad, enter the first digit of the security code, Response 300 will beep once. Enter the second digit of the security code, Response 300 will beep twice. Repeat for all remaining digits of the security code.

With the correct code entered Response 510 will announce the number of messages received and announce "please wait" while it winds to the correct position on the tape.

Should an incorrect code be entered, a second attempt may be made, if this is incorrect, Response 510 will hang up.

Memos and messages will be replayed automatically. Message replay will pause every 2.5 minutes and a pause tone will be heard for several seconds. During remote access, keying digits from the keypad or remote controller will allow the user to control the functions of the Response 510. See the user guide for a full explanation of the facilities.

Unless messages and memos are reset remotely, they will be saved automatically.

New units carry a 21 months warranty from the date of manufacture as shown on the year and week marking on the base of the instrument. These markings form the first 4 digits of the serial number.

British Telecom guarantees sold machines (excluding cassette tape and battery) for 12 months from the date of purchase irrespective of the date of manufacture.

Description						BT Item Code
Response 510 Combined LST / Ans & Rec Machine		870628
(Complete with transformer, tape and 3 x AAA batteries)
BT Remote Controller					870427
Transformer 752 9.5 volts dc:	white			870629
Transformer 752 9.5 volts dc:	Black			870471
Message Tape MC-60 Microcassette.			870435
Or any high quality, normal bias MC-60 tape purchased locally.
3 x AAA batteries.

Normal test conditions when waiting to answer. After answering the telephone and answering machine presents a loop resistance to line of approximately 328 ohms measured at 28mA. Additionally, the instruments will draw about 25mA on hook. This may appear to give apparent Low Loop line test conditions. With the handset off-hook, like many modern telephones, they may give high resistance telephone loop test conditions.

The ringing circuit has been designed to recognise both PSTN and all internal ringing cadences generated by BT PABXS. There is no manual ring facility.

2. CLEAR DETECT Line Break Clear/Release from line.
Modern exchanges generate a 100 ms line break on the called parties line when the calling party clears down, this is a called a disconnect clear signal. Response 510 will detect this signal and immediately release from the line without the need to wait for network tones.

When the machine answers the line, it checks whether paytone is present. If paytone is detected, the announcement is delayed for up to 15 seconds.

This facility causes the machine to release the line when a telephone connected to the same line is taken off-hook. For about 1 second before and after answering this facility is inhibited. This prevents the false release of the machine from line due to line ringing (current surge to & fro) when answering.

The handset and keypad are line powered. The Loudspeaking facility and answering/recording features of are mains powered from the 9.5 volt dc plug top transformer.

In the event of a mains failure all mains dependent facilities cease to function. Restoration of the mains supply will automatically reset the machines to answer whether or not they were set to "answer" before the supply failed. Response 510 will announce "Please wait" and the display will show WAIT for a few seconds after power is restored.

This is a system default condition and cannot be overridden. Messages received before the power failure are not lost and can be played back remotely or by using the play button on the machine.

If the mains power is removed together with the batteries and line power, all customer stored information will be lost and the Response 510 will revert back to it's default settings.

The cassette cover, which is located under the memory label must be in place for the Response 510 to make and receive calls.

On-site maintenance of the Response range is limited as the equipment contains no serviceable parts. Some routine servicing - detailed in the User Guide should be carried out by the customer, but field maintenance is restricted to checking the facility switch settings and testing the power unit output.

Several adapters used with Response instruments are marked with lower outputs than those actually measured. Approximate voltage readings (with the output open circuit) are as follows:-
Transformer 19B (marked 13.5V DC) measures 19 - 20v.
Transformer 752 (marked 9V AC) measures 11 - 12v.
Transformer 753 (marked 9.5V DC) measures 13 - 14v.


It has been reported that a large quantity of the Response range of TARMs have been returned as faulty without being fully reset and retried. Some faults are caused by quick line disconnects and Radio Frequency Interference and may be cleared by a reset.

Models such as the Response 200, 300, 400, 510 & 1000 have all got a reset button on the underside of the unit. Depressing this button momentarily, using a small probe, will perform a slightly different reset to that performed when the mains is turned off/on. It is suggested that this is performed first, then retry all facilities, before changing out the unit.

However, if after changing the unit the same fault recurs on the new unit, the problem may be site specific and changing the unit again will be of no advantage. If this is the case, please contact the Technical Helpdesk for further advise.

A major problem with Response TARMs recording after a message has been left has been caused by the exchange equipment presenting 'clicks' on the line when it is idle. This is due to a modified line card on System X exchanges. BT Labs are aware of the problem and are investigating a cure. Changing the unit will not clear this problem. 

The cause has been identified as the 'end of call signal' (Disconnect Clear Time) which indicates to the machine that the call has finished but also prevents the Response 510 forwarding a valid message. A modified version is available but it is recommended that the DCT is reduced to l00ms before requesting a modified unit. Please contact the Helpdesk for details on obtaining these units.

A few instances of this problem have been reported.


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Last revised: October 30, 2022