4923
The Tektronix 4923 is a tape drive for the 4006 and 4010 Series Terminals with RS-232 data communication. It is nearly identical in appearance to the 4924. The only differences seem to be the 4923 has a selectable communications baud rate from 110 to 9600, where as the 4924 is fixed at 9600. Also the capacity of the tapes for the 4923 is 200,000 bytes and 300,000 bytes per cartridge for the 4924.
The 4923 uses DC300A/300A cartridges with a 200KB capacity but may also be compatible with the 300XL Data Cartridges.