On the one side, you have the standard keypad for dialling numbers.
At Bordeaux his Universal Tables on Dialling were constructed; and in London he was admitted to the meetings of Robert Boyle, Robert Hooke and other learned and scientific men.
Their proceedings were very cautious and tentative; they excited the curiosity and interest of even the more intelligent Chinese by their clocks, their globes and maps, their books of European engravings, and by Ricci's knowledge of mathematics, including dialling and the projection of maps.
He published, among other mathematical works, Clavis Mathematica, in 1631, in which he introduced new signs for certain mathematical operations (see Algebra); a treatise on navigation entitled Circles of Proportion, in 1632; works on trigonometry and dialling, and his Opuscula Mathematica, published posthumously in 1676.
