This part is a kind of semiconductor called 8251A.

Function of this product has PROGRAMMABLE COMMUNICATION INTERFACE.

Manufacturers : Rochester Electronics

Image and pinout :

Some of the text within the PDF file :

© 2012 Rochester Electronics, LLC. All Rights Reserved 12192012 8251A TdTdfSTrirneehahohicmcsetemelaeiuug8iU8dvttln2rth2eeSaae5e5dnndAd11eCsaRaAAfmootPTaucirsiUishsstwdrsulayaiaiintsrl,ohnltaeainpesstcdimactcgteiearaonniarscsnmdalshflualoerimnoestrlhpintcquftroeeheunyerreieiCmivrcpsreaCPophtaatrreUstPisneoeraUdsanwarneial.snadhndrTdlwedtethdlhncyiveatUeeohictinvnnnaCemeticPvrsuraooietsUcnirlnrteredssovccaai(epgaaimislnrrnnntocsSpsacalrryluaetesochndnascgsecidsdenruhmaopgccrtmrhtoohiInfenaBnmaatovoMmcnseueoedaiSsrl“mwti/beYbcAtpihsyoN-cslsenheytsDyhmtatnuineEenrcccauiThshnC”c,or)tttaPo.ToauetnTUsxsrupoEhsfasMtuoeMoerosrCarUPofitlSalrRptTSeahl-eleYAn4dedrc.s8RaaaeTUm,ttTtaiehvSa8iseeas0uAcsrtc,schRr/icoTieh8naTenrai5grpapam,aontvicsatsrsitfrnaemowdftadunrrahisbatyttiterarAleflaitonycr [ ... ]

8251A PDF Datasheet Download