Casella CEL CEL-393 - Manual (Page 41)

This output accurately follows the fast and slow time constants, but It
should be noted that when impulse is selected, both rise and fall times
of the output are constant at 35ms. However when peak time weighting
is selected, the rise and fall times of the DC output depend on the
matching impedance of the connected instrument.
The connector on the base also provides the external power input (see
Chapter 9), external synchronisation of filter, and the serial data output.
The latter two functions are available only on the B and D versions of the
instrument, and are fully described in Chapter 5.
The following standard cables are available for use with the CEL-393
and associated instruments.
C4187/2 CEL-393 to CEL-160 graphic recorder cable (AC),
C4167/2 CEL-393 to Uher 4000 series tape recorder.
4.5 Auxiliary Input
Inputs other than via the microphone may be made by means of the
CEL-216 Line Input Adaptor so that pre-recorded tapes may be analysed
by the CEL-393.
Warning
Do not apply signals larger than 35V RMS to the
input of the CEL-393.
The preamplifier forms an integral part of the instrument's gain switching
arrangements, which must be taken into account when using auxiliary
inputs. Hence measurements made using the CEL-216 adaptor should
be confined to the 10 to 70dB ranges.
393 Handbook /37.