CallZone

CallZone was a service offered by PageLink, a subsidiary of SingTel (then known as Telecommunications Equipment) in the 1990s. The service allowed users to make, but not receive, calls using a special handset made by Motorola, in certain designated zones. The technology was similar to CT2-based services already established earlier in the UK, Germany, Hong Kong, and elsewhere.

Description
When exactly the CallZone service was introduced is unclear. It is widely stated that the service was introduced sometime in 1991 or 1992. However, an article from July 1994 states that the service was introduced in May 1994.

Users who subscribed to the service were given a Motorola-made flip-phone, the Silverlink 2000 Birdie to make calls. These calls could only be made in certain areas with a CALLZONE sign; as of August 2019, some of these signs can still be found around the island. . Handsets were sold at S$350 each in July 1994.

The network was shut down in October 1998. In a letter to 3,500 subscribers explaining the shutdown, SingTel said that the service was not financially viable because of the emergence of low-cost cellular handsets. Additionally, Motorola had stopped making the handsets.

Criticism
It was reported that areas with CALLZONE base stations also had payphones located in the vicinity, which made having a Callzone phone somewhat pointless.

In 1993, The Straits Times also reported that too many users were making calls on their zonephones at the same time, thus jamming the network.

SingTel CallZone
The CallZone name was resurrected for a service, also offered by SingTel. The service allows SingTel subscribers to make free mobile phone calls, using a special device connected to a SingNet Broadband modem.