Siemens DAG 64¶
This looks like a modem, but it actually isnt. It doesn't contain any actual modulation/demodulation circuits, but communicates in baesband. Hence it's called "Daten-Anschalt-Geraet" (something like data-connection-device in German) for use not in the public PSTN/telephone network, but in a parallel leased line data network Datex-L, possibly also for Datex-P.
In those networks, the modem did not have to transport data over hundreds or thousands of kilometers end-to-end to the called party, but only on the last mile between the central office for data exchange and the subscriber. This is why higher bitrates (like in this example 64kBps) could be achieved, which were never reached over end-to-end telephone lines.