Difference between revisions of "Anderson Jacobson A 242"
m |
m (update from chatgpt) |
||
| (One intermediate revision by the same user not shown) | |||
| Line 5: | Line 5: | ||
| intro_month = May | | intro_month = May | ||
}} | }} | ||
| − | The | + | The '''A 242''' modem was introduced in May 1975 by |
| − | | id=CdkopCC9Q0QC | + | Anderson Jacobson. It was designed as an originate-only |
| − | | pg=54 | + | acoustic coupler modem and served as the successor to the |
| − | | title="Six AJ Devices make Debut" | + | Anderson Jacobson ADC 260.{{Computerworld |
| − | | date=May 14, 1975 | + | | id = CdkopCC9Q0QC |
| + | | pg = 54 | ||
| + | | title = "Six AJ Devices make Debut" | ||
| + | | date = May 14, 1975 | ||
| + | | name = cw19750514 | ||
}}{{Computerworld | }}{{Computerworld | ||
| − | | id=8pMVcgpPyVMC | + | | id = 8pMVcgpPyVMC |
| − | | page=19 | + | | page = 19 |
| − | | title=Anderson Jacobson advertisement | + | | title = Anderson Jacobson advertisement |
| − | | date=July 23, 1975 | + | | date = July 23, 1975 |
| + | | name = cw19750723 | ||
}} | }} | ||
| + | ==Background== | ||
| + | |||
| + | In the mid-1970s, growth in time-sharing services and | ||
| + | remote terminal access created sustained demand for | ||
| + | portable data communications equipment. Contemporary trade | ||
| + | press coverage described the A 242 as one of six new | ||
| + | devices introduced by the company in May 1975.<ref | ||
| + | name="cw19750514" /> | ||
| + | |||
| + | The A 242 followed the earlier ADC 260 and continued the | ||
| + | company’s emphasis on compact acoustic coupler designs. | ||
| + | The introduction of distinct originate and answer models | ||
| + | reflected a common industry practice, allowing customers | ||
| + | to assemble complete communication links by pairing | ||
| + | complementary units. | ||
| + | |||
| + | ==Technical characteristics== | ||
| + | |||
| + | The A 242 was an '''originate modem''', meaning that it | ||
| + | generated the calling tones required to establish a data | ||
| + | connection over the public switched telephone network. | ||
| + | Under Bell System conventions then widely followed in the | ||
| + | United States, originate modems transmitted at 1,070 Hz | ||
| + | and received at 2,025 Hz, with answer modems using the | ||
| + | opposite frequency arrangement. | ||
| + | |||
| + | As an '''acoustic coupler''', the A 242 interfaced with a | ||
| + | standard telephone handset rather than connecting directly | ||
| + | to the telephone line. The handset was placed into molded | ||
| + | rubber cups that acoustically coupled the telephone’s | ||
| + | microphone and earpiece to the modem’s transducers. This | ||
| + | design avoided direct electrical connection to the | ||
| + | telephone network, which at the time was subject to | ||
| + | regulatory limitations in many jurisdictions. | ||
| + | |||
| + | The modem was intended for use with asynchronous serial | ||
| + | data from terminals and similar equipment. In operation, | ||
| + | it would be paired with a compatible answer modem at the | ||
| + | remote site to form a complete communication path. | ||
| + | |||
| + | ==Product line context== | ||
| + | |||
| + | Advertising later in 1975 continued to promote the A 242 | ||
| + | within the company’s acoustic coupler portfolio, | ||
| + | indicating its role as a current production model during | ||
| + | that year.<ref name="cw19750723" /> | ||
{{references}} | {{references}} | ||
| Line 22: | Line 73: | ||
[[Category:Anderson Jacobson|A 242]] | [[Category:Anderson Jacobson|A 242]] | ||
[[Category:Modem]] | [[Category:Modem]] | ||
| + | [[Category:Acoustic Coupler]] | ||
[[Category:1975]] | [[Category:1975]] | ||
| − | |||
Latest revision as of 06:21, 1 March 2026
| Anderson Jacobson A 242 | |
|---|---|
| Manufacturer | Anderson Jacobson |
| Model | A 242 |
| Lifetime | |
| Introduced | May, 1975 |
The A 242 modem was introduced in May 1975 by Anderson Jacobson. It was designed as an originate-only acoustic coupler modem and served as the successor to the Anderson Jacobson ADC 260.[1][2]
Background
In the mid-1970s, growth in time-sharing services and remote terminal access created sustained demand for portable data communications equipment. Contemporary trade press coverage described the A 242 as one of six new devices introduced by the company in May 1975.[1]
The A 242 followed the earlier ADC 260 and continued the company’s emphasis on compact acoustic coupler designs. The introduction of distinct originate and answer models reflected a common industry practice, allowing customers to assemble complete communication links by pairing complementary units.
Technical characteristics
The A 242 was an originate modem, meaning that it generated the calling tones required to establish a data connection over the public switched telephone network. Under Bell System conventions then widely followed in the United States, originate modems transmitted at 1,070 Hz and received at 2,025 Hz, with answer modems using the opposite frequency arrangement.
As an acoustic coupler, the A 242 interfaced with a standard telephone handset rather than connecting directly to the telephone line. The handset was placed into molded rubber cups that acoustically coupled the telephone’s microphone and earpiece to the modem’s transducers. This design avoided direct electrical connection to the telephone network, which at the time was subject to regulatory limitations in many jurisdictions.
The modem was intended for use with asynchronous serial data from terminals and similar equipment. In operation, it would be paired with a compatible answer modem at the remote site to form a complete communication path.
Product line context
Advertising later in 1975 continued to promote the A 242 within the company’s acoustic coupler portfolio, indicating its role as a current production model during that year.[2]
References
- ↑ 1.0 1.1 "Six AJ Devices make Debut", Computerworld, May 14, 1975, pg. 54
- ↑ 2.0 2.1 Anderson Jacobson advertisement, Computerworld, July 23, 1975, pg. 19
