This particular model Western Electric phone
was used in the dormitories at the college my wife and I attended in Orlando,
Florida back in the early 1970's. Known as the "554" series, it had the
same network, dial, ringer and handset as the common 500 model.
Schematics (only a few have been
scanned and made available so far):
Instructions on how to remove the plastic housing from the
base is provided here in a series of photos.
CLICK ON SMALL PHOTOS BELOW TO SEE FULL-SIZE PHOTOS:
The release for the latch that holds the
plastic cover housing on the 554 phone is located in the center of the
lower part of the phone between where the handset cord is attached and the
loudness control lever for the bell ringer. The "trick" to releasing
this latch is to apply moderate pressure to the housing with one hand (see
Step 1 photo which follows these instructions) while at the same time
pushing in the latch release tab as shown in Photo 2 below.