Response 20 Response 50

The BT Response 20 (left) and Response 50 (right) are mains powered, single tape processor controlled Answering and Recording machines giving many advanced facilities within a compact case design and may be desk or wall mounted.  These machines use Micro-cassettes as the storage media.

The Response 20 and Response 50 facilities are as follows:-

  • Announcement - Up to 2 minutes. Press and hold ANNOUNCEMENT/RECORD CHECK button to record your announcement, release on completion.
  • Announcement Record/Check - Press ANNOUNCEMENT/RECORD CHECK button once briefly.
  • Audible Alert - Set AUDIBLE ALERT switch to ON if beep required to indicate that messages have been recorded. Volume control must be turned up.
  • Incoming Messages - Up to 3 minutes. Total message time is about 28 minutes using a standard Microcassette MC60 tape.
  • Memo Message - No limit, up to end of tape. Press and hold the MEMO button to record, release on completion.
  • Message Play - Press PLAY once briefly. This will play all messages and memos.
  • Message Save - After The Response 20 or Response 50 has reset to answer, press and hold the SAVE button until machine beeps once.
  • Sensitivity - NORMAL and LOW, switchable. Pre-set to NORMAL
  • Branchphone reset - Will release machine from the line should a parallel telephone handset be lifted. This facility is inhibited for up to 3 seconds when machine first answers, therefore the facility may not always appear to operate.
  • Call Screening - Volume Control must be turned up to listen.
  • Pause - Maximum pause is 60 seconds. Press PLAY/PAUSE once while listening to messages, press PLAY/PAUSE again to continue. After 60 seconds the Response resets and all messages are saved.
  • Volume Control - Slider switch, from minimum to maximum.
  • Answer Delay - SHORT answers after 2 rings. LONG answers after 6 rings.
  • Remote set to Answer - Call machine and let it ring 20 times to turn machine on remotely. Mains supply to machine must be turned on.
  • Extra facilities on the Response M are as follows:-

    Answer Delay - SHORT answers after 2 rings. LONG answers after 6 rings. TS (time saver). Answers after 2 rings if messages are recorded or answers after 6 rings if no messages are recorded.

    Integral phone socket - Does away with need for phonesocket doubler. NOTE:- A phonesocket doubler is required if a telephone is to be used with the Response 20.

    Time and Day stamp - As long as the time and day have been set an announcement confirming how many messages have been recorded will be made. Also, the time and day will be given after every recorded message.

Remote Access
The method of accessing messages remotely on the Response 50 is as follows:-

By responding to tone signals from an MF remote controller, or a telephone with MF signalling, after listening to the announcement. After the announcement is played and the long tone is heard press #. This gives the access mode and confirmation is given with two beeps. The two security digits must now be keyed, (the code is on a label inside cassette compartment) waiting for the beep response after each digit is keyed.

If the code was correct the number of messages recorded will be announced and then played. After the last message an announcement indicating the end of messages will be made.

Up to two attempts can be made to interrogate the machine remotely, if unsuccessful on the second attempt the machine releases the line. Other attempts can then be made.

Made by Team Concepts International Ltd. (Malaysia)

Approval Numbers
Response 20 S/1000/3/N/502551
Response 50 S/1000/3/N/502550

Approved as supplied for connection to the Public Switched Telephone Network (PSTN) and PBX 2-wire extensions.
The Response 20 and Response 50 are not approved for use on Shared Service lines or as an extension to a payphone. They are not suitable for use on PBX's where manual ringing is applied.

A Phone Socket and a 240 volts. 13 amp, 50 Hertz mains supply are required within 2.5 metres of the Response 20 or Response 50. The Response 20 and Response 50 are suitable for use on Phone Socket installations on DELs and most types of PBX extensions that provide automatic ringing. A doubler will be required if a telephone is used in conjunction with the Response 20. (The Response 50 has an integral phone socket). The Response 20 and Response 50 both have a Ringer Equivalence Number (REN) of 1 and are intended for use in normal Domestic, Residential or Business locations. They are not suited for use in bathrooms or other locations prone to damp or condensation.

Approximate overall dimensions are:-
Response 20 and Response 50. 135 mm x 205 mm x 54 mm, weight 910 grams.

The machine contains no on-site serviceable parts, therefore maintenance is limited to functional testing, checking the output of the plug-top transformer. that the line and telephone cords are correctly positioned and the facility switches are set for optimum performance of the machine to match the line to which it is connected. The condition of the tape should be checked; i.e. is it too tight on its spool, or is it badly creased or torn. The play head should be inspected for cleanliness and if suspect, a replacement tape should be purchased and the tape head cleaned.

If the machine has failed completely, the output voltage of the Transformer should be checked. The output is marked 9V AC, but will measure about 12volts when tested with the output open circuit. The Response 20 and Response 50 use the same transformer.

The customer is advised in the User Guide to change the tape at six monthly intervals, turning the tape over once after three months. On each occasion the tape is changed or turned over, the tape head should be cleaned and a new OGM must be recorded.

New units carry a 21 month warranty from the date of manufacture, identified by the first 4 digits YY WW **** (Year and Week) of the serial number marked on the underside of the machine.

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.

Description				        BT Item Code
Response 20, Alpine White                  	870507
(Complete with Transformer)
Response 50, Charcoal Grey                 	870508
(Complete with Transformer)
BT Remote Interrogator                     	870427
Message Tape MC 60 Microcassette           	870435
Adaptor 753                                	870505

Taken from BT Customer Service Information No. 271


New production of Response 50 instruments have had the music, “Frere Jacques”, removed which is normally played whilst the tape is fast forwarding when in answer mode. Production models with serial numbers greater than 94330392552 have had the music removed and replaced with a series of slow beeps. This product originally played approximately 20 bleeps before the musical version was introduced around December 1993.

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, 500 & 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.

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. 


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Last revised: October 31, 2021