IBM 2740 & 2741 Communications Terminal

Contents

Background

The IBMs 2740 and 2741 were printer-keyboard based communications terminals released in July 1965^[2][2]
IBM - DPD chronology - 1965 [accessed 2021-07-22]. for use with IBM System/360 computers. They were remote I/O terminals that provided direct access to the computer via a multiplexor and were ideally suited for text handling, online computation and programming applications^[3][3]
IBM - IBM 2741 Communications Terminal Systems Reference Library (#A24-3415-2) [accessed 2022-09-16]. and even other terminals in the case of 2740s. Both the 2740 and 2741 feature a Selectric-based IBM 72 I/O Typewriter using then-end Solid Logic Technology (SLT) circuitry and the ability to be used as a standard typewriter as needed^[4][4]
IBM - IBM 2740 & 2741 Communications Terminal field engineering announcement (#229-9501-0) [accessed 2022-09-05].. The 2740s were intended for applications such as payment entry, journal entries, inquiries, administrative messages, file updating and renewals^[5][5]
IBM - IBM 2740 Model 1, 2740 Model 2 & 2741 Communications Terminal Theory of Operation (#SY27-0013-4) [accessed 2022-09-16]., whereas 2741 was primarily intended for use in the IBM Administrative Terminal System (ATS)^[5][5]
IBM - IBM 2740 Model 1, 2740 Model 2 & 2741 Communications Terminal Theory of Operation (#SY27-0013-4) [accessed 2022-09-16]..

2740 Model 1

The IBM 2740 Model 1 (aka, 2740-1) along with the 2740-2 were members of the 274x series that could communicate with either a host computer or other terminals, requiring a common-carrier data set or IBM modem line adapter. Compared to 2740-2, 2740-1 is non-buffered and cannot store and print out characters for verification before transmission. Its non-typewriter keys were small and circular.

2740 Model 2

The IBM 2740 Model 2 (aka, 2740-2) along with the 2740-1 were members of the 274x series that could communicate with either a host computer or other terminals, requiring a common-carrier data set or IBM modem line adapter. The 2740-2 is a buffered version of 2740-1 that can store up to 120 characters and print them for verification before transmission. Its non-typewriter keys were rectangular.

2741

The IBM 2741 was the only member of the 274x series to be limited to just communicating to a host computer instead of as well other terminals. In fact, its operations are controlled by host computer programming. 2741 thus lacks a few keys that 2740 has and even uses a different typing element^[5][5]
IBM - IBM 2740 Model 1, 2740 Model 2 & 2741 Communications Terminal Theory of Operation (#SY27-0013-4) [accessed 2022-09-16].. Due to being a Selectric-based device, the print element could be replaced with ones that had APL legends^[7][7]
Columbia University - The IBM 2741 Terminal [accessed 2021-07-22]..

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