RS232 transceiver in a through-hole DIP — what the 250 kBd and 400 mV hysteresis mean for your serial link
The 400 mV of receiver hysteresis cleans up noisy signals on longer cable runs, reducing the chance of a false start bit on an idle line.
Second-source option — ADM202JNZ as a pin-compatible alternative
It matches the full-duplex RS232 protocol, 2/2 driver/receiver count, 400 mV receiver hysteresis, 18-DIP through-hole package, and the same 4.5 V supply minimum. The data rate is identical at 250 kBd, and the temperature range is also 0°C to 70°C. The ADM202JNZ can be qualified as a drop-in alternate without board respin.