Page "Synchronous Data Link Control" Paragraph 6

Intel used SDLC as a base protocol for BITBUS, still popular in Europe as fieldbus and included support in several controllers ( i8044 / i8344, i80152 ).

The 8044 controller is still in production by third party vendors.

Other vendors putting hardware support for SDLC ( and the slightly different HDLC ) into communication controller chips of the 1980s included Intel, Zilog, Motorola, and National Semiconductor.

As a result, a wide variety of equipment in the 1980s used it and it was very common in the mainframe centric corporate networks which were the norm in the 1980s.

The most common alternatives for SNA with SDLC were probably DECNET with DDCMP, BDLC, and ARPANET with IMPs.