Search results for "Telephone network"
showing 3 items of 3 documents
Toll-quality digital secraphone
2002
This paper describes the design and performance of a secraphone that, when plugged between any conventional telephone set and the public telephone network, protects the speech information travelling through the PSTN. The device has a transparent operating mode that does not alter the signal and a secure mode, accessed upon request of any of the speakers, that encrypts the speech with digital techniques, assuring privacy against unwanted listeners. At the transmission branch, voice is sampled, coded with a CELP scheme at 9600 bps (with a slow mode at 7200 bps), encrypted with a proprietary algorithm and interfaced to the line with a V.32 modem chip set. The keys for encryption are establishe…
Mobile telephony in emerging markets: The importance of dual-SIM phones
2020
Abstract A substantial share of customers in emerging markets use dual-SIM phones and subscribe to two mobile networks. A primary motive for so called multi-simming is to take advantage of cheap on-net services from both networks. In our modelling effort, we augment the seminal model of competing telephone networks á la Laffont, Rey and Tirole (1998b) by a segment of flexible price hunters that may choose to multi-sim. According to our findings, in equilibrium, the networks set a high off-net price in the linear tariffs to achieve segmentation. This induces the price hunters to multi-sim. We show that increased deployment of dual-SIM phones may induce a mixing equilibrium with high expected…
Mobile Telephony in Emerging Markets: The Importance of Multi-Simming Customers
2015
Rapidly increasing sales of multi-SIM phones, mobile penetration rates above 100% and reported customer behavior all point to the fact that a signicant share of mobile customers in emerging markets tend to use more than one SIM card. A primary motive for this is to avoid making expensive o-net calls. We add a segment of exible prepaid customers, who choose to "multi-sim" in equilibrium, to the seminal model of competing telephone networks a la Laont,