Dial Radio Frequency Interference Filters - WE 61-type

[paul-f]

There are numerous forum topics on identifying components that turn out to be 61-type Filters.

Here are some good references that describe and show some of the many variations that were made that include mounting brackets for major telephone set types.

From BSP C18.071.00, issue 1, June, 1960
https://www.telephonecollectors.info/index.php/search?q=c18.071.00

2.01 The 61-type filter is designed specifically for use in connection with station dials to suppress radio frequency induction into radio receivers, due to dialing. It may, however, be used with other equipment and circuit arrangements under suitable operating conditions.

3.02 Each of the 61B, D, E, F, G, H, J, L, M, N, P, R, and S filters consists of a 61A filter mounted with two mounting screws mounted on a bracket which varies in design according to the apparatus with which it is to be used (see Fig.2).

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From C18.071.01, issue 1, October, 1960
https://www.telephonecollectors.info/index.php/search?q=c18.071.01

1.02 This section covers the installation (locating and mounting) of and connections for the 61-type filters when such filters are installed in desk stands, handset mountings, telephone sets, subscriber sets (with dials or buzzers), and coin collectors. (Example below.)

The many diagrams are interesting as they show both location and cording info.

[paul-f]

Connections for specific sets are also often shown in BSPs for the specific model numbers.

For example, for 300-type sets...

[paul-f]

An alternative for 61-type filters to eliminate radio interference is the 152A Condenser.