Apple Personal Modem
| Apple Personal Modem | |
|---|---|
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|
| Apple Personal Modem with its plug head fitted, beside the user's manual (photo: Apple Rescue of Denver) | |
| Manufacturer | Apple Computer, Inc. |
| Type | 300/1200 bit/s external modem |
| Release date | 1985 |
| Interface | RS-232-C on an 8-pin mini-circular socket; two RJ-11 telephone jacks |
| Compatible | Apple II family with a Super Serial Card, Apple IIc, Apple III, Lisa and Macintosh XL, Macintosh, other computers with an RS-232 port |
| Power | Mains, through a detachable plug head on the modem body |
| Part number | 661-0313 (service whole unit); 933-0001 (plug head) |
The Apple Personal Modem is a small 300 and 1200 bit/s modem that plugs straight into a mains socket. Apple released it in April 1985.[1] It has no DIP switches: the speed, parity and duplex are set from the communications software, and the modem answers to the Hayes command set.[2][3] The modem body and the plug head are separate modules; Apple serviced the modem by exchanging the body, and sold the plug head on its own.[2]
Specifications
[edit | edit source]| Item | Value |
|---|---|
| Standards | Bell 103 (0-300 bit/s) and Bell 212A (1200 bit/s) |
| Software speeds | 110, 300 and 1200 baud[2] |
| Data format | Asynchronous; 7 data bits with 1 or 2 stop bits and odd, even, mark, space or no parity, or 8 data bits with 1 or 2 stop bits and no parity; full duplex |
| Dialling | Tone (DTMF) or pulse at 10 pulses per second; automatic or manual dial and answer |
| Receiver dynamic range | −10 to −45 dBm |
| Transmit level | −10 dBm, fixed |
| Interface | RS-232-C, 8-pin mini-circular socket |
| Telephone connectors | Two RJ-11 jacks |
| Indicator | One light, on while connected to another modem (data carrier detect) |
| FCC registration | BCG794-12381-DM-E; ringer equivalence 0.4B |
| Temperature | 0 to 45 °C operating; −20 to 65 °C storage |
All figures are from Apple's specification article except where marked.[4]
The modem beeps once when it is plugged in, after a short self-test that cannot be turned off.[4] Either RJ-11 jack can go to the telephone line: the modem detects the line voltage and sets the other jack up for a telephone.[4] Apple listed the Apple II, II Plus and IIe with a Super Serial Card or compatible serial card, the Apple IIc, the Apple III, the Macintosh, the Macintosh XL and the Lisa, and any computer with an RS-232 port. An Apple IIc with a serial number of 510,000 or lower needed an upgrade from an Apple dealer first, which Apple offered free.[4]
Connections
[edit | edit source].png)
| Mini-DIN pin | Signal | Direction | DB-25 (RS-232) pin |
|---|---|---|---|
| 1 | Data Set Ready (DSR) | From modem | 6 |
| 2 | Data Terminal Ready (DTR) | To modem | 20 |
| 3 | Receive Data (RXD) | From modem | 3 |
| 4 | Signal ground | 7 | |
| 5 | Transmit Data (TXD) | To modem | 2 |
| 6 | Signal ground | 7 | |
| 7 | Data Carrier Detect (DCD) | From modem | 8 |
| 8 | Not connected |
The DB-25 column is Apple's wiring for a cable to an IBM-compatible PC or any other RS-232 port.[5] The pin numbering printed on page 84 (Figure F-1) of the Apple Personal Modem User's Manual, part number 030-2001-C, is wrong. Seen from the back of the modem, the socket's top row reads 8, 7, 6, the middle row 5, 4, 3 and the bottom row of two pins 2, 1.[6]
Apple gives two sets of cable part numbers. The specification article lists 590-0331 (Apple II, II Plus, IIe, III and Macintosh XL), 590-0332 (Apple IIc) and 590-0333 (Macintosh).[4] The Illustrated Parts List of December 1987 lists 590-0555 (Apple II, II Plus, IIe, Apple III and Macintosh XL), 590-0551 (Macintosh), 590-0554 (Apple IIc), 590-0552 (Macintosh Plus) and the RJ-11 cable 076-8075; the three Macintosh and IIc cables are described as APM/ImageWriter II cables.[2] Apple warned that using an unshielded cable could breach the FCC's Class B limits.[4]
Commands and registers
[edit | edit source]The modem uses the Hayes command set, prefixed AT. Settings such as the number of rings before answering and the escape character are held in S registers.[3] Three defaults differ from what users of other modems expect:
- S0, auto-answer, defaults to 0, so the modem does not answer incoming calls until it is set. The Apple Modem 300/1200 defaults to answering on the first ring.[7]
- S9, the carrier-detect response time, is fixed at 0.6 seconds.[3][8]
- S16 selects the self-test; ATS16=1D starts the analogue loopback test.[3][2]
Use outside the United States
[edit | edit source]The modem follows the Bell 103 and Bell 212A standards used in the United States. Apple stated that it cannot be used in Australia or in many other countries, whose telephone systems use different standards.[9]
Troubleshooting
[edit | edit source]Apple's tests (power, computer link and analogue loopback), its symptom chart and the known faults are on the Apple Personal Modem Troubleshooting Guide.
Documentation
[edit | edit source]- Apple Modems Documentation: the Modems tab of Apple's Service Technical Procedures (section 2 and Figure 3 cover this modem) and the Service Source modems chapter.
Related pages
[edit | edit source]References
[edit | edit source]- ↑ Wikipedia, "List of Apple products", https://en.wikipedia.org/wiki/List_of_Apple_products (retrieved 2026-10-04). Source for: release date 1 April 1985.
- ↑ 2.0 2.1 2.2 2.3 2.4 Apple Computer, Apple Service Technical Procedures: Cross Family Peripherals, Volume One (part number 072-0230, March 1991 build), Modems tab, section 2, "Apple Personal Modem", pp. 2.1-2.5 (rev. April 1987), and Illustrated Parts List, Figure 3, pp. IPL.6-IPL.7 (rev. December 1987). Hosted as File:Apple Technical Procedures Modems (1991).pdf, PDF pp. 15-19 and 57-58. Source for: no DIP switches; 110, 300 and 1200 baud; the two-module construction and exchange rule; power, computer and self-test procedures; part numbers 661-0313, 933-0001 and the cables.
- ↑ 3.0 3.1 3.2 3.3 Apple Computer, "Apple Personal Modem: The commands and what they do", Tech Info Library article 1305 (TA30015), 1989. Archive.org item APPLE_TIL_ARTICLES, file TIL00001_to_TIL60496.zip (retrieved 2026-10-04). Source for: the Hayes command set, the command list and the S registers, S7 default 30 seconds, S9 fixed at 0.6 seconds, S16 self-test.
- ↑ 4.0 4.1 4.2 4.3 4.4 4.5 Apple Computer, "Apple Personal Modem: Specifications (Discontinued)", Tech Info Library article 1303. Archive.org item APPLE_TIL_ARTICLES, file TIL00001_to_TIL60496.zip. Source for: FCC registration and ringer equivalence; power-up self-test and beep; data format; Bell 103 and 212A; RS-232-C interface; dialling; receiver range and transmit level; temperature ranges; the indicator light; the two RJ-11 jacks either of which can take the line; the detachable plug head; Hayes compatibility; the supported computers and the interface cables 590-0331, 590-0332 and 590-0333.
- ↑ Apple Computer, "Apple Personal Modem: Pinouts for IBM-Compatible PCs", Tech Info Library article 2443 (TA37386), reviewed 13 January 1988; the same table is article 1304 (TA30006). Archive.org item APPLE_TIL_ARTICLES, file TIL00001_to_TIL60496.zip. Source for: the mini-circular 8 to DB-25 wiring.
- ↑ Apple Computer, "Apple Personal Modem: Correction to User's Manual", Tech Info Library article 2807 (TA37941), reviewed 30 March 1988; also article 1951 (TA35224). Archive.org item APPLE_TIL_ARTICLES, file TIL00001_to_TIL60496.zip. Source for: the error in Figure F-1 on page 84 of manual 030-2001-C; the corrected socket and plug numbering.
- ↑ Apple Computer, "Apple Personal Modem: Making it Work with AppleLine", Tech Info Library article 2220 (TA36944), 1989. Archive.org item APPLE_TIL_ARTICLES, file TIL00001_to_TIL60496.zip. Source for: S0 defaults to 0 on the Personal Modem and 1 on the Modem 300/1200; setting S0=1 for AppleLine; cables 590-0331 and 590-0029.
- ↑ Apple Computer, "Apple Personal Modem: Carrier detect", Tech Info Library article 1981 (TA35502). Archive.org item APPLE_TIL_ARTICLES, file TIL00001_to_TIL60496.zip. Source for: S9 fixed at 0.6 seconds; lengthening S7 with ATS7x (1 to 255 seconds; default 30) for software that misses the carrier.
- ↑ Apple Computer, "Apple Personal Modem: Can't Be Used In All Countries", Tech Info Library article 2874 (TA37982), reviewed 13 April 1988. Archive.org item APPLE_TIL_ARTICLES, file TIL00001_to_TIL60496.zip. Source for: Bell 103 and 212 are US standards; the modem cannot be used in Australia or many other countries.