They had the messaging devices first, then a messaging device with a headset for phone calls, then a phone. Which did you mean?
Wikipedia has:
Early pager models:
These two-way pager models had thumb keyboards, with a thumbwheel for scrolling its monochrome text display. The first model, the Inter@ctive Pager, was announced on September 18, 1996.[
Monochrome Java-based models (5000 and 6000 series)
The 5810 was released on March 4, 2002.[4]
5810 large monochrome screen 1900 MHz GSM/GPRS phone but headset required