Popcom (an abbreviation of Popular Communications[1]) was a line of modems marketed by the Prentice Corporation of Sunnyvale, California, introduced in 1984.

The X100—the flagship product in the Popcom range—is an external modem, housed in a beige[4] plastic case with a built-in AC power adapter.

The only status indicators on the unit itself are provided through aural means, via short bursts of three touch tones generated from the speaker.

Prentice laid out three Hayes commands that could not be utilized by the X100, namely echoing and those pertaining to transmitting over amateur radio, but these were seldom used by the vast majority of personal computer users.

Such a zip tone occurring during a data transmission usually proved fatal for the connection, but the Popcom could have carried on after such an interruption and continue receiving data, albeit with errors in the stream, which may have been correctable with error detection schemes and retransmission capabilities of some online services contemporary to the Popcom.

[10] The human-voice detection capability allowed users to transmit data and speak to the recipient on the other end of the line within the same call.

The C100 and C150 are both full-length, XT-case-height expansion cards, with Will R. Rosch of PC Magazine noticing a fair amount of bodge wires on the board, overall calling its design "obviously dated" by 1987.

[1] The Popcom family were the first retail products of Prentice Corporation, a Sunnyvale-based company who had a long history of manufacturing modems for large businesses since their foundation in 1963.

[19] Stephen Satchell of InfoWorld called the Popcom X100 a "breeze to install" and attractive for users of portable computers in particular due to its small size.

The data/voice feature is useless for communicating with host computers or information utilities such as CompuServe ... but it's truly invaluable for exchanging data between microcomputers operated by people.

"[20] Rosch, also in PC Magazine, was more critical, calling the X100/X150 "a refreshingly original design of doubtful practicality", noting that the Popcom would be liable to slip out of worn-out electrical sockets due to its heft.

[14] Bill Lamb of The Paris News praised the X100's easy of use and out-of-sight nature and wrote that, "[f]or its price and characteristics, the X100 is a step ahead of the pack, as far as modems are concerned.