# ZTerm

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Shareware terminal emulator

ZTerm Developer David Alverson Release 1992; 34 years ago (1992) Stable release 1.2 / 18 July 2011; 14 years ago (2011-07-18) Operating system Mac OS 8, Mac OS 9, Mac OS X 10.0 through Mac OS X 10.7 Type Terminal emulator License Shareware Website dalverson.com/zterm/

**ZTerm** is a [shareware](/source/Shareware) [terminal emulator](/source/Terminal_emulator) for [Macintosh operating system](/source/Macintosh_operating_system). It was introduced in 1992 for [System 7](/source/System_7) and has been updated to run on [macOS](/source/MacOS). Its name comes from its use of the [ZModem](/source/ZModem) [file transfer protocol](/source/File_transfer_protocol), which ZTerm implemented in a particularly high-performance package. In contrast to the built-in macOS [Terminal](/source/Terminal_(macOS)) app, which only communicates with other programs, ZTerm only communicates with hardware [serial ports](/source/Serial_ports).

## Description

When it was first introduced in 1992, ZTerm was one of the highest-performing terminal emulators on the Mac, both in terms of basic text display as well as file transfer performance. ZTerm was widely regarded as the best terminal program on the Mac.[1][2][3]

Its hardware support included [carrier detect](/source/Data_Carrier_Detect) (CD), hardware hangup (DTR) and [hardware flow control](/source/Flow_control_(data)), as well as speeds up to 115,200 bit/s on those machines that supported it. These features were not universally supported in Mac hardware, so many terminal emulators simply didn't bother to implement them at all. Even if these speeds were offered, most emulator programs of the era were so slow that they had trouble keeping up with faster modems, especially 9600 bit/s and faster.[3]

ZTerm supported one of the widest variety of file transfer protocols available on the Mac, including a full implementation of ZModem, [YModem](/source/YModem), YModem-G, almost all of the common varieties of [XModem](/source/XModem) with different packet sizes and error correction methods,[3] and even the rare but useful [B protocol](/source/B_protocol) (CIS-B) for use on [Compuserve](/source/Compuserve). ZTerm also supported auto-starting transfers from ZModem and CIS-B, where commands from the host triggered transfers from the client.

Additionally, ZTerm included a complete [PC graphics character set](/source/Code_page_437) and [ANSI escape codes](/source/ANSI_escape_code), including color. This made it one of the few terminals on the Mac that properly displayed [ASCII art](/source/ASCII_art), and allowed full interaction with PC-based [bulletin board systems](/source/Bulletin_board_system) (BBS) that used these features extensively. ZTerm added the ability to use the mouse to position the cursor, sending the correct stream of ANSI codes to move it from the current to the clicked location.

Finally, ZTerm included a 10-verb built-in [scripting language](/source/Scripting_language) that allowed it to automate basic tasks. In addition to be able to run these manually, when a service was dialed using an entry in the editable Dial menu, ZTerm would look for a script with the same name and run it automatically.[3]

## Versions

The first public version of ZTerm was 0.9, which was released in 1992. Two major versions followed; 1.0 of April 1994 was a major release that added 16-color ANSI support instead of 8-color, user-selected fonts including [Shift JIS](/source/Shift_JIS) support, [Kermit](/source/Kermit_(protocol)) protocol support, and auto-opening of downloaded files. The latter was useful when used with [offline mail readers](/source/Offline_mail_reader) like Blue Wave. Version 1.0.1, released in October 1995, was mostly a bug-fix release.[4]

By 2002, the BBS world had largely disappeared. However, a number of devices (including some [routers](/source/Router_(computing)) and [lab equipment](/source/Lab_equipment)) still used serial ports to communicate, typically for diagnostic and debugging purposes. On 19 April 2001, Alverson released version 1.1b4 that ran on [Mac OS X 10.0](/source/Mac_OS_X_10.0), [Mac OS 8.6](/source/Mac_OS_8.6) and [Mac OS 9](/source/Mac_OS_9) using [Carbon](/source/Carbon_(API)).[5] Later a "Classic" version was released that did not require Carbon, allowing it to run on older machines that could not support Mac OS 8 or Mac OS 9. On 18 July 2011, Alverson released a Universal Binary version 1.2 that runs on [Mac OS X 10.4](/source/Mac_OS_X_10.4) through [Mac OS X 10.14](/source/Mac_OS_X_10.14). Because this version is not 64-bit, however, ZTerm will not run on [Mac OS X 10.15](/source/Mac_OS_X_10.15) and above.

On modern machines without built-in serial ports, ZTerm can identify and use a wide variety of [USB](/source/Universal_Serial_Bus)-based serial devices.[6] The list of supported hardware includes the standard [Macintosh serial ports](/source/RS-422#Characteristics) and [Geoport](/source/Geoport) on pre-[PowerPC G3](/source/PowerPC_G3) CPU [PowerPC](/source/PowerPC) Macintosh computers, the built-in Apple internal modem slot and the [USB](/source/USB) ports on [PowerPC G3](/source/PowerPC_G3), [PowerPC G4](/source/PowerPC_G4), [PowerPC G5](/source/PowerPC_G5), and [Intel-based Macintosh computers](/source/Mac_transition_to_Intel_processors). ZTerm can be configured to work with adapters, including various USB port to serial port adaptors (such as those made by Keyspan[7]) and Apple internal modem slot to serial port adaptors (such as the Stealth Serial Port[8] and the now-discontinued Griffin Technology gPort), giving it a unique use for BBSers and hardware tinkerers.

## References

1. **[^](#cite_ref-1)** Terrell, Rob (1994). [*Byte's Mac Programmer's Cookbook*](https://books.google.com/books?id=tmVGAAAAYAAJ). Osborne McGraw-Hill. p. 24. [ISBN](/source/ISBN_(identifier)) [9780078820625](https://en.wikipedia.org/wiki/Special:BookSources/9780078820625).

1. **[^](#cite_ref-2)** Eglowstein, Howard (1994). ["Advancing Communications"](https://books.google.com/books?id=iF9VAAAAMAAJ). *Byte*. p. 110.

1. ^ [***a***](#cite_ref-best_3-0) [***b***](#cite_ref-best_3-1) [***c***](#cite_ref-best_3-2) [***d***](#cite_ref-best_3-3) Thomson, Tom (July 1992). ["ZTerm Is Z-Best"](https://archive.org/details/byte-magazine-1992-07). *Byte*. p. 301.

1. **[^](#cite_ref-4)** Alverson, Dave. ["ZTerm"](http://www.dalverson.com/zterm/).

1. **[^](#cite_ref-5)** Sellers, Dennis (19 April 2001). ["ZTerm gains Mac OS X compatibility"](https://web.archive.org/web/20110611021729/http://www.macworld.com/article/17143/2001/04/zterm.html). [MacWorld](/source/MacWorld). Archived from [the original](http://www.macworld.com/article/17143/2001/04/zterm.html) on 11 June 2011. Retrieved 27 August 2017.

1. **[^](#cite_ref-6)** Alverson, Dave (30 June 2012). ["ZTerm - Macintosh Modem Communications"](http://www.dalverson.com/zterm/). Retrieved 27 August 2017.

1. **[^](#cite_ref-7)** ["Keyspan High Speed USB to Serial Adapter (USA-19HS) | Tripp Lite"](http://www.tripplite.com/keyspan-high-speed-usb-to-serial-adapter~USA19HS/). [Tripp Lite](/source/Tripp_Lite). Retrieved 26 August 2017.

1. **[^](#cite_ref-8)** ["GeeThree: Purchase"](https://web.archive.org/web/20170827130708/http://www.geethree.com/purchase/hardware.html). GeeThree.com. Archived from [the original](http://www.geethree.com/purchase/hardware.html) on 27 August 2017. Retrieved 27 August 2017.

## External links

- [Official website](http://dalverson.com/zterm/)

- [ZTerm 0.9 FAQ 1.6](https://web.archive.org/web/20190324161604/http://www.ralentz.com/old/mac/faqs/source/zterm.html) at the [Wayback Machine](/source/Wayback_Machine) (archived March 24, 2019)

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Adapted from the Wikipedia article [ZTerm](https://en.wikipedia.org/wiki/ZTerm) by Wikipedia contributors ([contributor history](https://en.wikipedia.org/wiki/ZTerm?action=history)). Available under [Creative Commons Attribution-ShareAlike 4.0 International](https://creativecommons.org/licenses/by-sa/4.0/). Changes may have been made.