Apple Data Modem 2400
| Apple Data Modem 2400 | |
|---|---|
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|
| The Data Modem 2400 and its external power adapter, drawn in Apple's Technical Procedures | |
| Manufacturer | Apple Computer, Inc. |
| Type | External data modem |
| Release date | 12 June 1989[1] |
| Discontinued | December 1992[2] |
| Interface | Mini-DIN-8 serial (RS-422A) |
| Compatible | Apple II family and Macintosh computers |
| Dimensions | 200 × 120 × 45 mm |
| Weight | 500 g without the power adapter |
| Power | External power adapter (service part 600-0455), 7 W maximum |
The Apple Data Modem 2400 is an external 2400 bit/s data modem that Apple sold for Apple II and Macintosh computers.[3] Apple introduced it on 12 June 1989 and sold it only through authorised Apple Desktop Communications dealers.[1] Wikipedia gives July 1989 for its introduction and December 1992 for its withdrawal.[2] Wikipedia's product list calls it the Apple Modem 2400; Apple's service documents use the full name Apple Data Modem 2400.[2][3]
The modem handles Bell 103 at 300 bit/s, Bell 212A and CCITT V.22 at 1200 bit/s, and CCITT V.22bis at 2400 bit/s. It takes an extended version of the Hayes command set, implements MNP error correction classes 1 to 4, dials by tone or pulse, and keeps its settings in non-volatile RAM.[3] Apple's ModemTest diagnostic covers it and the Portable Data Modem 2400, the internal modem for the Macintosh Portable.[4]
Hardware
[edit | edit source]Everything except the speaker and the external power adapter is on one printed circuit board, the main logic board. Some of the power supply circuitry is on that board, but most of it is inside the external adapter.[5]
Controls and indicators
[edit | edit source]There are three controls: a power switch on the back, a mode switch on the front between the two lights, and a speaker volume lever on the right-hand side. The lever has a detent at the middle of its range, and the speaker is built into the bottom of the case.[5][6] Green means the modem is active and ready. Amber means it is in pass-through mode, which it also shows briefly after power-on.[5] The mode switch does nothing while the modem is connected to a remote modem. Held down at power-up, it makes the modem reload its factory settings from ROM, the same as the AT&F command.[6]
In active mode the computer talks to the modem. In pass-through mode the modem is bypassed and the computer talks to whatever is plugged into the modem's second serial port. The mode select switch moves between the two.[7]
Connectors
[edit | edit source]| Connector | Icon | Use |
|---|---|---|
| Mini-DIN-8 serial | Macintosh | Cable to the computer |
| Mini-DIN-8 serial | Telephone handset | Pass-through port for a second serial device |
| RJ-11 | RJ-11 socket | Telephone line |
| RJ-11 | Telephone | Telephone set; disconnected while the modem is using the line |
| 5-pin DIN | Wall-mounted AC adapter | |
| Security socket | Security cable |
Only the computer port, the line jack and the power socket are needed for operation.[5][6] The ports cannot be swapped. The telephone-set jack is cut off while the modem is in use, and the serial signals are directional.[1] Only the inner two wires of the RJ-11 jacks (tip and ring) are passed through, which can upset PBX systems that signal on the outer pair; Apple's advice there was a separate line for the modem.[1]
The pass-through port is disabled while the modem is in use or switched off, and it cannot carry AppleTalk. Apple's Technical Procedures and two Tech Info Library articles print its top speed as "56.7 kilobits per second". Apple's question-and-answer article for its trainers gives 57.6 kbit/s, the limit set by the computer's Serial Communications Controller.[5][6][1][8]
| Pin | Name | Function |
|---|---|---|
| 1 | HSKo | CTS from modem |
| 2 | HSKi | DTR from computer |
| 3 | TxD- | Transmit data (-) |
| 4 | SGnd | Signal ground |
| 5 | RxD- | Receive data (-) |
| 6 | TxD+ | Transmit data (+) |
| 7 | GPi | DCD from modem |
| 8 | RxD+ | Receive data (+) |
| Shell | Ground | Chassis ground |
Power adapter
[edit | edit source]The Data Modem 2400 uses the same power connector as the Apple IIc and the AppleFax Modem. Their adapters plug in, but the modem will not power up from either of them. Apple says doing so does no damage to the modem or the adapter.[5][1] Apple's service part for the correct adapter is 600-0455.[9] The modem draws 7 W at most and Apple's US specification gives the supply as 110 V AC ±10%, 60 Hz.[10]
Specifications
[edit | edit source]| Item | Value |
|---|---|
| FCC registration number | BCG794-12381-DM-E |
| FCC ringer equivalence number | 1.1B |
| Canadian load number | 7 |
| Line jack | USOC RJ11 (US), CA 11 (Canada) |
| Protocol and mode | Asynchronous, full duplex |
| Rates | 300 bit/s (Bell 103); 1200 bit/s (V.22A/B and Bell 212A); 2400 (V.22bis) |
| Data formats | 7 data bits with 1 or 2 stop bits and fixed mark or space parity; 7 data bits with 2 stop bits and no parity; 8 data bits with 1 or 2 stop bits and no parity |
| Receiver dynamic range | -10 dBm to -43 dBm, full duplex (Technical Procedures); -10 to -45 dBm (Tech Info Library article 4306)[11] |
| Transmitter level | -10 dBm ±1 dB, fixed |
| Frequency tolerance | ±7 Hz |
| Error rate | Less than 1 in 106 on a 3002A unconditioned line with Gaussian noise, over a receiver level range of 3 dB above the carrier detect threshold |
| Error protocols | MNP classes 1 to 4 |
| Computer interface | RS-422A, Apple mini-DIN-8 connector |
| Tone dialling | DTMF, frequency tolerance ±1% |
| Pulse dialling | 39%/61% mark/break ratio, 10 pulses per second |
| Weight | 500 g without the power adapter |
| Dimensions | 200 × 120 × 45 mm |
| Power | 7 W maximum; 110 V AC ±10%, 60 Hz |
| Operating environment | 0-40 °C, 95% relative humidity non-condensing |
| Settings memory | Non-volatile RAM, rated for 10,000 write cycles[11] |
| Command buffer | 40 characters, not counting AT or spaces, dashes and brackets[11] |
Computers and cables
[edit | edit source]Apple's specification sheet lists these set-ups:[11]
| Computer | Interface cable |
|---|---|
| Macintosh Plus and later | M0197 |
| Macintosh 512K and earlier | M0196 |
| Apple II, Apple II Plus or Apple IIe with a Super Serial Card or compatible serial card | A2C0312 |
| Apple IIc with a serial number above 510,000 | A2C4313 |
| Apple IIc Plus and Apple IIGS | M0197 |
An Apple IIc with a serial number of 510,000 or lower needed a logic board upgrade, which Apple dealers fitted free.[11]
Service parts
[edit | edit source]Apple sold these parts separately for the Data Modem 2400.[9]
| Item | Part number | Description |
|---|---|---|
| 1 | 815-5073 | Top case |
| 2 | 661-0516 | Main logic board |
| 3 | 815-5076 | Volume lever |
| 4 | 600-0455 | Power supply |
| 5 | 630-5506 | Bottom case |
| 6 | 600-0403 | Speaker |
| 7 | 630-5505 | Light pipe assembly |
| 8 | 590-0590 | RJ-11 cable |
| 9 | 462-3100 | Screw, M3 × 0.5 × 6 |
Apple serviced the modem at module level, so the Technical Procedures and the later Service Source list modules and give no component values.[9][12]
Troubleshooting
[edit | edit source]Apple's own tests are a power-on self-test, a check that the modem answers AT with OK, an analog loopback test, and the ModemTest diagnostic disk.[13] A modem that will not connect to a bulletin board often has bad settings stored in it. Hold down the Select button while switching the modem off and on, and release it once the green light is lit, to restore the defaults.[13] The Apple Data Modem 2400 Troubleshooting Guide covers these tests, Apple's symptom chart and the take-apart.
Documentation
[edit | edit source]- Apple Modems Documentation: Apple's Technical Procedures for the 300/1200 modems, Personal Modem and Data Modem 2400 (1991), and the Service Source for Apple's modems (1995).
Related pages
[edit | edit source]- Apple Data Modem 2400 Troubleshooting Guide
- Apple Modem 1200 (covers the Apple Modem 300)
- Macintosh Portable
References
[edit | edit source]- ↑ 1.0 1.1 1.2 1.3 1.4 1.5 Apple Computer, Tech Info Library article 4305, "Apple Data Modem 2400: Overview", reviewed 29 August 1989. Copy at absurdengineering.org. Introduced 12 June 1989; sold only by authorised Apple Desktop Communications dealers; features; support issues: wrong power supply does not power the modem but causes no damage, only the inner two RJ-11 lines (tip and ring) pass through, factory reset by AT&F or holding the Mode button at power-up, telephone and serial ports must be used as marked.
- ↑ 2.0 2.1 2.2 Wikipedia, "List of Apple products", 1989 table (read 4 October 2026). Lists the "Apple Modem 2400" as introduced in July 1989 and discontinued in December 1992. History and dates only.
- ↑ 3.0 3.1 3.2 Apple Computer, Apple Service Technical Procedures: Cross Family Peripherals, Volume One (part number 072-0230, March 1991 build), Modems tab, section 3, p. 3.3 (Aug 1989). Hosted as File:Apple Technical Procedures Modems (1991).pdf. Product overview: external stand-alone modem for Apple II and Macintosh computers; automatic and manual dialling and answering; DTMF and pulse dialling; extended Hayes command set; local and remote self-test; MNP levels 1 to 4; Bell 103, Bell 212A, CCITT V.22A/B and V.22bis; two serial ports and two RJ-11 connectors; settings held in non-volatile RAM.
- ↑ Apple Computer, Apple Service Technical Procedures: Cross Family Peripherals, Volume One, Modems tab, section 4 (Diagnostics), pp. 4.1-4.3 (Aug 1990 and Mar 1991). ModemTest runs the modem's self-tests (RAM, ROM and microprocessor), command tests, register tests, analog tests, digital tests, a speaker test, a pass-through mode test (Data Modem 2400 only) and a ring detect test; it does not test the telephone-line interface, which Apple checked by calling AppleLink.
- ↑ 5.0 5.1 5.2 5.3 5.4 5.5 Apple Computer, Apple Service Technical Procedures: Cross Family Peripherals, Volume One, Modems tab, section 3, pp. 3.4-3.6 (Aug 1989 and Apr 1990). Controls (power switch, mode select switch, speaker volume control), green and amber indicators, connectors, power adapter compatibility note, daisy-chain port speed, and theory of operation (single main logic board; most power supply circuitry in the external adapter).
- ↑ 6.0 6.1 6.2 6.3 Apple Computer, Tech Info Library article 4300, "Apple Data Modem 2400: Pinouts and Hardware Description", reviewed 29 August 1989. Copy at absurdengineering.org. Front panel LEDs and Mode switch; volume lever on the right side; speaker in the bottom of the case; back panel on/off switch, two RJ-11 jacks, two mini-DIN-8 serial ports with the computer-port pinout, 5-pin DIN power connector and security cable socket.
- ↑ Apple Computer, Apple Service Technical Procedures: Cross Family Peripherals, Volume One, Modems tab, section 3, p. 3.4 (Aug 1989). Active and pass-through modes; the pass-through connector is marked with a telephone handset.
- ↑ Apple Computer, Tech Info Library article 3944, "Apple Data Modem 2400: Q & A from LAN Minds Training", created 8 June 1989, updated 22 July 1993. Copy at absurdengineering.org. Maximum pass-through speed 57.6 kbit/s, set by the computer's Serial Communications Controller; the modem negotiates an MNP link of class 4 or lower.
- ↑ 9.0 9.1 9.2 Apple Computer, Apple Service Technical Procedures: Cross Family Peripherals, Volume One, Modems tab, Illustrated Parts List, pp. IPL.8-IPL.9 (Aug 1989), Figure 4 and parts list for the Apple Data Modem 2400.
- ↑ 10.0 10.1 Apple Computer, Apple Service Technical Procedures: Cross Family Peripherals, Volume One, Modems tab, section 3, pp. 3.7-3.8 (Apr 1990). Specifications for the US and Canadian version.
- ↑ 11.0 11.1 11.2 11.3 11.4 Apple Computer, Tech Info Library article 4306, "Apple Data Modem 2400: Specifications (Discontinued)", created 18 September 1989. Copy at absurdengineering.org. Specifications, including receiver dynamic range -10 to -45 dBm, non-volatile RAM rated for 10,000 write cycles, 40-character command buffer, power-up self-test with two beeps, and system configuration with interface cables.
- ↑ Apple Computer, Service Source: Modems (PDF dated November 1995, from the Service Source 2.5 CD of 1997). Hosted as File:Apple Service Source Modems (1995).pdf. Take Apart, Apple Data Modem 2400, pp. 1-6 (cover, logic board, speaker); Troubleshooting, Symptom Charts, Apple Data Modem 2400, p. 2.
- ↑ 13.0 13.1 Apple Computer, Apple Service Technical Procedures: Cross Family Peripherals, Volume One, Modems tab, section 3, pp. 3.14-3.17 (Aug 1989 and Mar 1991). Troubleshooting: software-configured settings; resetting the parameters with the Select button; power-on test sequence (amber light, self-test, two tones, green light); communications test; analog loopback test with ATS16=1D.