[GreenKeys] Modem

[Jim Haynes]

The modem pictured is undoubtedly for use with a Model 33, or maybe
a Model 35.  Now the other thing that comes up is that it is an
originate-only modem.  That's all that is needed when the modem user
calls the computer, which is the way those things are used.  But it
can't talk to a similar modem because it only uses the originate
frequencies.  The modem at the other end has to use the opposite set
of frequencies.  Modems for TWX and DataPhone service are able to
originate and answer calls; but the overwhelming majority of simple
modems are originate only.

jhhaynes at earthlink dot net