OS2/30
OS2/31
OS2/31A
OS2/32
OS2/33
OS2/34
OS2/35
OS2/35A
OS2/36
OS2/37
OS2/38
OS2/39
OS2/50l
OS2/502A-E
OS2/503
OS2/505
OS2/505A
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OS2
Fixed Frequency Oscillator, l48.8kHz used in Split Band
apparatus. DD 1967. DD Spec 2.305. OBSOLESCENT.
Fixed Frequency Oscillator, 23kHz, used to provide pilot
tone for transmitters and capable of being keyed by
information pulses. PS2/22B can be accommodated if
required. CH1/12A. DD 1968. ACO. OBSOLESCENT.
As 052/31 but frequency set to 19kHz.
WITHDRAWN .
DD 1968.
Fixed Frequency Oscillator, 100kHz, used in MN1L/5. Mains
operated. CH1/18. DD 1968. WITHDRAWN.
Used for Voice Frequency Ringing to provide 4 frequencies
in the range 450Hz-1900Hz. Supersedes OS2/l. Operates
from either 12V or 24V supplies. CH1/18C, pegs 20, 34.
DD 1968. DD Spec 2.273. OBSOLESCENT.
Fixed Frequency Oscillator, 100kHz, for supplying drive to
AMl/30. Used on BRT/2 Magnetic Recorder. CH1/18C.
DD 1968. CANCELLED.
Tone Monitoring Oscillator
Includes PS2/22E. CH1/l2A.
ACO. OBSOLESCENT.
(23kHz) superseding OS2/5A.
DD 1968. DD Spec 5.144.
Similar to OS2/35 but has a regulator card fitted in place
of PS2/22E for use with a -50V supply instead of mains.
DD 1968. DD Spec 5.144. OBSOLESCENT.
Ringing Current Oscillator, 25Hz, 50V, used in PAlM/67.
Commercial oscillator housed in CH1/18E, pegs 22, 42.
Replaced by OS2/47. DD 1968. ACO. OBSOLESCENT.
100kHz Oscillator used to drive AMl/31. ISEP board with
25 way plug, coding positions 3, 9, 17. DD 1969.
DD Spec 1.78. DDTM 1.61. ACO. OBSOLESCENT.
Twin Fixed Frequency Oscillator used in EP1M/ll, EPlM/12
to provide dual clock or dual b1eep tone drive. Basically
two 052/26. Printed board with 25 way ISEP plug, coding
3, 7, 25. DD 1969. CANCELLED.
DD 1971. WITHDRAWN.
IF unit used on RClA/505. DD 1962. ACO. OBSOLESCENT.
RF units used on RC1A/505. Suffixes indicate Band 1
Channels 1, 2, 3, etc. DD 1962. OBSOLESCENT.
Commercial 4.4296875Mc/s crystal oscillator mounted in
CHl/12B. Used in GE1/517. DD 1963. WITHDRAWN.
Used GE1/520. Frequency: 4.4296875MHz.
DD 1964. DDTM 10.23. ACO. OBSOLESCENT.
CH1/12B.
As 052/505 but with improved resistance to machanical

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